Routing Command Reference for Cisco ASR 9000 Series Routers

address-family (IS-IS)

To enter address family configuration mode for configuring Intermediate System-to-Intermediate System (IS-IS) routing that use standard IP Version 4 (IPv4) and IP Version 6 (IPv6) address prefixes, use the address-family command in router configuration or interface configuration mode. To disable support for an address family, use the no form of this command.

address-family {ipv4 | ipv6} {unicast | multicast}

no address-family {ipv4 | ipv6} {unicast | multicast}

Syntax Description


ipv4	Specifies IPv4 address prefixes.
ipv6	Specifies IPv6 address prefixes.
unicast	Specifies unicast address prefixes.
multicast	Specifies multicast address prefixes.

Command Default

An address family is not specified. The default subaddress family (SAFI) is unicast.

Command Modes

Router configuration

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the address family command to place the router or interface in address family configuration mode. In router address family configuration mode, you can configure routing that uses standard IPv4 or IPv6 address prefixes. An address family must be specified in interface configuration mode. In interface address family configuration mode, you can alter interface parameters for IPv4or IPv6.

You must specify an address family in order to configure parameters that pertain to a single address family.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the IS-IS router process with IPv4 unicast address prefixes:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface gigabitEthernet 0/1/0/0 
  RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-if-af)#

address-family multicast topology (IS-IS)

To enable a multicast topology when configuring Intermediate System-to-Intermediate System (IS-IS) routing (or to place a given topology within the IS-IS interface), use the address-family multicast topology command with either IPv4 or IPv6 address prefix in the appropriate configuration mode. To disable a multicast topology in IS-IS, use the no form of this command.

address-family {ipv4 | ipv6} multicast topology topo-name [maximum prefix prefix-limit]

no address-family

Syntax Description


ipv4	Specifies IPv4 address prefixes.
ipv6	Specifies IPv6 address prefixes.
multicast	Specifies multicast address prefixes.
topology `topo-name`	Specifies the name of the topology.
maximum prefix	Specifies maximum number of prefixes that a routing table can have.
`prefix-limit`	Maximum number of prefixes. Range is from 32 to 2,000,000.

Command Default

An address family for multicast topology is not specified. The default subaddress family (SAFI) is unicast.

Command Modes

Router configuration

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the address family multicast topology command to place the router or interface in address family configuration mode. In router address family configuration mode, you can associate an IS-IS topology ID with the topology you have created to add connected and local routes to a specific routing table.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the IS-IS router topology with an IPv4 multicast address prefix:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# address-family ipv6 multicast topology green
RP/0/RSP0/CPU0:router(config-isis-af)#

or


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)#  interface gigabitethernet 0/3/0/0
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 multicast topology green
RP/0/RSP0/CPU0:router(config-isis-if-af)#

Related Commands


Command	Description
topology-id	Associates a topology ID with a named IS-IS topology to differentiate topologies in the domain.

adjacency-check disable

To suppress Intermediate System-to-Intermediate System (IS-IS) IP Version 4 (IPv4) or IP Version 6 (IPv6) protocol-support consistency checks that are performed prior to forming adjacencies on hello packets, use the adjacency-check disable command in address family configuration mode. To remove this function, use the no form of this command.

adjacency-check disable

no adjacency-check disable

Command Default

Adjacency check is enabled

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support was added for ipv6.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

IS-IS performs consistency checks on hello packets and forms an adjacency only with a neighboring router that supports the same set of protocols. A router running IS-IS for both IPv4 and IPv6 does not form an adjacency with a router running IS-IS for IPv4 only.

Use the adjacency-check disable command to suppress the consistency checks for IPv6 IS-IS and allow an IPv4 IS-IS router to form an adjacency with a router running IPv4 IS-IS and IPv6. IS-IS never forms an adjacency between a router running IPv4 IS-IS only and a router running IPv6 only.

In addition, the adjacency-check disable command suppresses the IPv4 or IPv6 subnet consistency check and allows IS-IS to form an adjacency with other routers regardless of whether they have an IPv4 or IPv6 subnet in common.

Task ID


Task ID	Operations
isis	read, write

Examples

The command in the following example disables the adjacency checks:

The following example shows how the network administrator introduces IPv6 into an existing IPv4 IS-IS network and ensures that the checking of hello packet checks from adjacent neighbors is disabled until all neighbor routers are configured to use IPv6:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv6 |ipv4
  RP/0/RSP0/CPU0:router(config-isis-af)# adjacency-check disable

advertise passive-only

To configure IS-IS to advertise only prefixes that belong to passive interfaces, use the advertise-passive-only command in ISIS address family configuration mode. To disable advertisement only prefixes that belong to passive interfaces, use the no form of this command.

advertise passive-only

no advertise passive-only

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes

IPv4 unicast address family configuration

IPv4 multicast address family configuration

IPv6 unicast address family configuration

IPv6 multicast address family configuration

Command History


Release	Modification
Release 4.2.0	This command was introduced.
Release 5.0.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to configure IS-IS to advertise only prefixes that belong to passive interfaces.

RP/0/RSP0/CPU0:router#configure 
RP/0/RSP0/CPU0:router(config)#router isis isp
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4 unicast  
RP/0/RSP0/CPU0:router(config-isis-af)#advertise passive-only

adjacency stagger (IS-IS)

To configure staggering of IS-IS adjacency during reload, process restart, and process clear, use the adjacency stagger command in router configuration mode. To turn off adjacency staggering, either use the disable keyword or use the no form of this command.

adjacency stagger {disable | initial-num-nbr max-num-nbr}

no adjacency stagger


disable	Disables adjacency staggering.
`initial-num-nbr`	The initial number of simultaneous neighbors allowed to form adjacency to FULL in any area to bring up to FULL after a router reload, IS-IS process restart, or IS-IS process clear. Range is 1-65535. Default is 2.
`max-num-nbr`	The subsequent number of simultaneous neighbors allowed to form adjacency, per IS-IS instance, after the initial set of IS-IS neighbors have become FULL. Range is 1-65535. Default is 64.

Command Default

IS-IS adjacency staggering is enabled.

Command Modes

Router configuration

Table 1. Command History
Release	Modification
Release 6.3.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Staggering of the IS-IS adjacency during reload, process restart (without NSR or graceful-restart), and process clear reduces the overall adjacency convergence time.

Initially, allow 2 (configurable) neighbors to form adjacency to FULL per area. After the first adjacency reaches FULL, up to 64 (configurable) neighbors can form adjacency simultaneously for the IS-IS instance (all areas). However, areas without any FULL adjacency is restricted by the initial area limit.

Note

Adjacency stagger and IS-IS nonstop forwarding (NSF) are mutually exclusive. Adjacency stagger is not activated if nonstop forwarding (NSF) is configured in the router along with IS-IS configuration.

Table 2. Task ID
Task ID	Operations
IS-IS	read, write

Examples

The following example shows how to configure adjacency stagger for a 2 neighbors initially and for a maximum of 32 neighbors:

Router# configure
Router(config)# router isis 1
Router(config-isis)# adjacency stagger 2 32

algorithm 0

The algorithm 0 command allows you to override the maximum-paths configuration for an address-family and IS-IS instance pair. The maximum-paths subcommand under algorithm 0 configuration block will be applied to the standard SPF algorithm of that IS-IS instance.

algorithm 0

address-family { ipv4 | ipv6 | } unicast

maximum-paths maximum-paths

Syntax Description


address-family {ipv4 \| ipv6}	Configures the address family for IS-IS.
unicast	Specifies unicast address prefixes.
maximum-paths	Specifies the maximum number of parallel routes that an IP routing protocol installs in the routing table. The range is 1 to 64.

Command Modes

IS-IS interface

Command History


Release	Modification
Release 7.8.1	This command was introduced.

Usage Guidelines

No specific guidelines impact the use of this command.

Task ID


Task ID	Operations
isis	read, write

attached-bit receive ignore

To ignore the attached bit in a received Level 1 link-state packet (LSP), use the attached-bit receive ignore command in address family configuration mode. To remove the attached-bit receive ignore command from the configuration file and restore the system to its default condition, use the no form of this command.

attached-bit receive ignore

no attached-bit receive ignore

Command Default

The attached bit is set in the LSP.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.8.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure to ignore the attached bit in a received LSP:


RP/0/RSP0/CPU0:router(config)# router isis isp1
RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-af)# attached-bit receive ignore

Related Commands


Command	Description
attached-bit send	Configures an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit in the Level 1 link-state packet (LSP).

attached-bit send

To configure an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit in the Level 1 link-state packet (LSP), use the attached-bit send command in address family configuration mode. To remove the attached-bit send command from the configuration file and restore the system to its default condition, use the no form of this command.

attached-bit send {always-set | never-set}

no attached-bit send {always-set | never-set}

Syntax Description


always-set	Specifies to always set the attached bit in the LSP.
never-set	Specifies to never set the attached bit in the LSP.

Command Default

The attached bit is not forced to be set or unset in the LSP.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.8.0	This command was introduced and replaces the set-attached-bit command.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the attached-bit send command to set an IS-IS instance with an attached bit in the Level 1 LSP that allows another IS-IS instance to redistribute Level 2 topology. The attached bit is used when the Level 2 connectivity from another IS-IS instance is advertised by the Level 1 attached bit.

Cisco IOS XR software does not support multiple Level 1 areas in a single IS-IS routing instance; however the equivalent functionality is achieved by redistribution of routes between two IS-IS instances by using the redistribute (IS-IS) command.

The attached bit is configured for a specific address family only if the single-topology command is not configured.

Note

If connectivity for the Level 2 instance is lost, the attached bit in the Level 1 instance LSP continues sending traffic to the Level 2 instance and causes the traffic to be dropped.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit:


RP/0/RSP0/CPU0:router(config)# router isis isp1
RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-af)# attached-bit send always-set

Related Commands


Command	Description
redistribute (IS-IS)	Redistribute routes from one routing protocol into Intermediate System-to-Intermediate System (IS-IS).
single-topology	Configures the link topology for IPv4 when IPv6 is configured.

authentication-check disable

To suppress Intermediate System-to-Intermediate System (IS-IS) authentication check, use the authentication-check disable command in configuration mode. To remove this function, use the no form of this command.

authentication-check disable

no authentication-check disable

Command Default

Authentication check is enabled

Command Modes

Global Configuration mode

Command History


Release	Modification
Release 7.7.1	This command was introduced.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to disable authentication check for IS-IS.

Router# configure
Router(config)# router isis 1
Router(config)# authentication-check disable
Router(config)# commit

circuit-type

To configure the type of adjacency used for the Intermediate System-to-Intermediate System (IS-IS) protocol, use the circuit-type command in interface configuration mode. To reset the circuit type to Level l and Level 2, use the no form of this command.

circuit-type {level-1 | level-1-2 | level-2-only}

no circuit-type

Syntax Description


level-1	Establishes only Level 1 adjacencies over an interface.
level-1-2	Establishes both Level 1 and Level 2 adjacencies, if possible.
level-2-only	Establishes only Level 2 adjacencies over an interface.

Command Default

Default adjacency types are Level 1 and Level 2 adjacencies.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Adjacencies may not be established even if allowed by the circuit-type command. The proper way to establish adjacencies is to configure a router as a Level 1, Level 1 and Level 2, or Level 2-only system using the is-type command. Only on networking devices that are between areas (Level 1 and Level 2 networking devices) should you configure some interfaces to be Level 2-only to prevent wasting bandwidth by sending out unused Level 1 hello packets. Remember that on point-to-point interfaces, the Level 1 and Level 2 hello packets are in the same packet.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a Level 1 adjacency with its neighbor on GigabitEthernetinterface 0/2/0/0 and Level 2 adjacencies with all Level 2-capable routers on GigabitEthernet interface 0/5/0/2:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# is-type level-1-2
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# circuit-type level-1
  RP/0/RSP0/CPU0:router(config-isis-if)# exit
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/5/0/2
  RP/0/RSP0/CPU0:router(config-isis-if)# circuit-type level-2-only

In this example, only Level 2 adjacencies are established because the is-type command is configured:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# is-type level-2-only
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# circuit-type level-1-2

Related Commands


Command	Description
is-type	Configures the routing level for an instance of the IS-IS routing process.
net	Configures an IS-IS NET for the routing process.

clear isis process

To clear the link-state packet (LSP) database and adjacency database sessions for an Intermediate System-to-Intermediate System (IS-IS) instance or all IS-IS instances, use the clear isis process command in EXEC configuration mode.

clear isis [instance instance-id] process

Syntax Description


instance `instance-id`	(Optional) Specifies IS-IS sessions for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No default behavior or values

Command Modes

EXEC configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the clear isis process command without any keyword to clear all the IS-IS instances. Add the instance instance-id keyword and argument to clear the specified IS-IS instance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows the IS-IS LSP database and adjacency sessions being cleared for instance 1:

RP/0/RSP0/CPU0:router# clear isis instance 1 process

Related Commands


Command	Description
show isis database	Displays the IS-IS link-state database.
show isis neighbors	Displays information about IS-IS neighbors.

clear isis route

To clear the Intermediate System-to-Intermediate System (IS-IS) routes in a topology, use the clear isis route command in EXEC configuration mode.

clear isis [instance instance-id] {afi-all | ipv4 | ipv6} {unicast | multicast | safi-all} [topology topo-name] route

Syntax Description


instance `instance-id`	(Optional) Specifies IS-IS sessions for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.
afi-all	Specifies IP Version 4 (IPv4) and IP Version 6 (IPv6) address prefixes.
ipv4	Specifies IPv4 address prefixes.
ipv6	Specifies IPv6 address prefixes.
unicast	Specifies unicast address prefixes.
multicast	Specifies multicast address prefixes.
safi-all	Specifies all secondary address prefixes.
topology `topo-name`	(Optional) Specifies topology table information and name of the topology table.

Command Default

No default behavior or value

Command Modes

EXEC configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the clear isis route command to clear the routes from the specified topology or all routes in all topologies if no topology is specified.

Task ID


Task ID	Operations
isis	execute
rib	read, write
basic-services	read, write

Examples

The following example shows how to clear the routes with IPv4 unicast address prefixes:

RP/0/RSP0/CPU0:router# clear isis ipv4 unicast route

Related Commands


Command	Description
show isis database	Displays the IS-IS link-state database.
show isis neighbors	Displays information about IS-IS neighbors.

clear isis statistics

To clear the Intermediate System-to-Intermediate System (IS-IS) statistics, use the clear isis statistics command in EXEC configuration mode.

clear isis [instance instance-id] statistics [type interface-path-id]

Syntax Description

instance instance-id

(Optional) Clears IS-IS sessions for the specified IS-IS instance only.

The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

No default behavior or values

Command Modes

EXEC configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the clear isis statistics command to clear the information displayed by the show isis statistics command.

Task ID


Task ID	Operations
isis	execute
rib	read, write
basic-services	read, write

Examples

The following example shows the IS-IS statistics for a specified interface being cleared:

RP/0/RSP0/CPU0:router# clear isis instance 23 statistics

Related Commands


Command	Description
show isis statistics	Displays the IS-IS statistics.

cost-fallback anomaly delay

cost-fallback anomaly delay { igp-metric | te-metric } { increment penalty_value | multiplier penalty_multiplier | value penalized_metric | disable }

Syntax Description


increment `penalty_value`	Increment the IGP cost by the specified value. The range is from 1 to 65534.
multiplier`penalty_multiplier`	Multiply the IGP cost by the specified value. The range is from 1 to 255.
value `penalized_metric`	Set the IGP cost to the specified value. The range is from 1 to 65535.

Command Modes

Interface Configuration

Area Configuration

Router Configuration

Command History


Release	Modification
Release 7.4.1	This command was introduced.

Usage Guidelines

Use the cost-fallback anomaly delay command to increase the metric when you configure link delay anomaly detection in Segment Routing Performance Measurement (SR-PM).

When you configure link delay anomaly detection, SR-PM sends an anomaly bit (A-bit) when the upper bound of the anomaly threshold is exceeded. When an anomaly is received for an interface, OSPF can increase the IGP metric or TE metric to make the link less attractive for traffic.

You can specify how to increase the metric in the following ways:

As a factor by which the base metric is multiplied
As an increment that is added to the base metric
As a fixed high value (up to 0xFFFFFFFF).

Note

Due to protocol limitations, there is a maximum value applied for the metric for all three options:

IGP metric maximum value: 0xFFFF
TE metric maximum value: 0xFFFFFFFF

The configuration can be applied at the OSPF interface, area, and instance levels, and is applicable only to non-loopback interfaces. When the configuration is applied at the OSPF interface level, it is applicable to that interface only.

Task ID


Task ID	Operation
ospf	read, write

Examples

In the following examples, the base IGP metric values are 10.

This example shows how to increase the IGP and TE metrics for an interface. The IGP metric will be increased by 10 and the TE metric will be multiplied by 10. When an anomalous bit notification comes for interface GigabitEthernet0/2/0/0, the values advertised in the TLVs will be IGP metric 20 and TE metric 100.

Router(config)# router ospf 1
Router(config-ospf)# area 0
Router(config-ospf-ar)# interface GigabitEthernet 0/2/0/0
Router(config-ospf-ar-if)# cost-fallback anomaly delay igp-metric increment 10
Router(config-ospf-ar-if)# cost-fallback anomaly delay te-metric multiplier 10

This example shows how to set a specific IGP and TE metric value for an interface. When an anomalous bit notification comes for interface GigabitEthernet0/2/0/0, the values advertised in the TLVs will be IGP metric 100 and TE metric 50.

Router(config)# router ospf 1
Router(config-ospf)# area 0
Router(config-ospf-ar)# interface GigabitEthernet 0/2/0/0
Router(config-ospf-ar-if)# cost-fallback anomaly delay igp-metric value 100
Router(config-ospf-ar-if)# cost-fallback anomaly delay te-metric value 50

csnp-interval

To configure the interval at which periodic complete sequence number PDU (CSNP) packets are sent on broadcast interfaces, use the csnp-interval command in interface configuration mode. To restore the default value, use the no form of this command.

csnp-interval seconds [level {1 | 2}]

no csnp-interval seconds [level {1 | 2}]

Syntax Description


`seconds`	Interval (in seconds) of time between transmission of CSNPs on multiaccess networks. This interval applies only for the designated router. Range is 0 to 65535 seconds.
level { 1 \| 2 }	(Optional) Specifies the interval of time between transmission of CSNPs for Level 1 or Level 2 independently.

Command Default

seconds : 10 seconds

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The csnp-interval command applies only to the designated router (DR) for a specified interface. Only DRs send CSNP packets to maintain database synchronization. The CSNP interval can be configured independently for Level 1 and Level 2.

Use of the csnp-interval command on point-to-point subinterfaces makes sense only in combination with the IS-IS mesh-group feature.

Task ID


Task ID	Operations
isis	execute
rib	read, write
basic-services	read, write

Examples

The following example shows how to set the CSNP interval for Level 1 to 30 seconds:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/0/2/0
  RP/0/RSP0/CPU0:router(config-isis-if)# csnp-interval 30 level 1

default-information originate (IS-IS)

To generate a default route into an Intermediate System-to-Intermediate System (IS-IS) routing domain, use the default-information originate command in address family configuration mode. To remove the default-information originate command from the configuration file and restore the system to its default condition, use the no form of this command.

default-information originate [route-policy route-policy-name]

no default-information originate [external | route-policy route-policy-name]

Syntax Description


route-policy	(Optional) Defines the conditions for the default route.
`route-policy-name`	(Optional) Name for the route policy.

Command Default

A default route is not generated into an IS-IS routing domain.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

If a router configured with the default-information originate command has a route to 0.0.0.0 in the routing table, IS-IS originates an advertisement for 0.0.0.0 in its link-state packets (LSPs).

Without a route policy, the default is advertised only in Level 2 LSPs. For Level 1 routing, there is another process to find the default route, which is to look for the closest Level 1 and Level 2 router. The closest Level 1 and Level 2 router can be found by looking at the attached-bit (ATT) in Level 1 LSPs.

A route policy can be used for two purposes:

To make the router generate the default route in its Level 1 LSPs.
To advertise 0.0.0.0/0 conditionally.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to generate a default external route into an IS-IS domain:


 RP/0/RSP0/CPU0:router(config)# router isis isp
 RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
 RP/0/RSP0/CPU0:router(config-isis-af)# default-information originate

Related Commands


Command	Description
redistribute (IS-IS)	Redistributes routes from one routing protocol into Intermediate System-to-Intermediate System (IS-IS).
show isis database	Displays the IS-IS link-state database.

disable (IS-IS)

To disable the Intermediate System-to-Intermediate System (IS-IS) topology on a specified interface, use the disable command in interface address family configuration mode. To remove this function, use the no form of this command.

disable

no disable

Command Default

IS-IS protocol is enabled.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to disable the IS-IS protocol for IPv4 unicast on GigabitEthernet interface 0/1/0/1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-if-af)# disable

distance (IS-IS)

To define the administrative distance assigned to routes discovered by the Intermediate System-to-Intermediate System (IS-IS) protocol, use the distance command in address family configuration mode. To remove the distance command from the configuration file and restore the system to its default condition in which the software removes a distance definition, use the no form of this command.

distance weight [prefix mask | prefix/length | | [prefix-list-name]]

no distance [weight] [prefix mask | prefix/length | | [prefix-list-name]]

Syntax Description


`weight`	Administrative distance to be assigned to IS-IS routes. Range is 1 to 255.
`prefix`	(Optional) The prefix argument specifies the IP address in four-part, dotted-decimal notation.
`mask`	(Optional) IP address mask.
`/length`	(Optional) The length of the IP prefix. A decimal value that indicates how many of the high-order contiguous bits of the address compose the prefix (the network portion of the address). A slash must precede the decimal value. Range is 0 to 32 for IPv4 addresses and 0 to 128 for IPv6 addresses.
`prefix-list-name`	(Optional) List of routes to which administrative distance applies.

Command Default

weight : 115

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

An administrative distance is an integer from 1 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means that the routing information source cannot be trusted at all and should be ignored. Weight values are subjective; no quantitative method exists for choosing weight values.

Use the distance command to configure the administrative distances applied to IS-IS routes when they are inserted into the Routing Information Base (RIB), and influence the likelihood of these routes being preferred over routes to the same destination addresses discovered by other protocols.

The address/prefix-length argument defines to which source router the distance applies. In other words, each IS-IS route is advertised by another router, and that router advertises an address that identifies it. This source address is displayed in the output of the show isis route detail command.

The distance command applies to the routes advertised by routers whose address matches the specified prefix. The prefix-list-name argument can then be used to refine this further so that the distance command affects only specific routes.

Task ID


Task ID	Operations
isis	read, write

Examples

In the following example, a distance of 10 is assigned to all routes to 2.0.0.0/8 and 3.0.0.0/8 (or more specific prefixes) that are advertised by routers whose ID is contained in 1.0.0.0/8. A distance of 80 is assigned to all other routes.


  RP/0/RSP0/CPU0:router(config)# ipv4 prefix-list target_routes
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# permit 2.0.0.0/8
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# permit 3.0.0.0/8
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# deny 0.0.0.0/0 
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# exit
  RP/0/RSP0/CPU0:router(config)# router isis isp 
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# distance 10 1.0.0.0/8 target_routes 
  RP/0/RSP0/CPU0:router(config-isis-af)# distance 80

Related Commands


Command	Description
router isis	Configures the IS-IS routing protocol and specifies an IS-IS instance.
show isis protocol	Displays summary information about the IS-IS instance.
show isis route detail	Displays link-state packet (LSP) details.

distribute-list in (IS-IS)

To filter the routes that Intermediate System-to-Intermediate System (IS-IS) installs in the Routing Information Base (RIB), use the distribute-list in command in the appropriate configuration mode. To change or remove the filter, use the no form of this command.

distribute-list { { prefix-list prefix-list-name | route-policy route-policy-name} } in

no distribute-list { { prefix-list prefix-list-name | route-policy route-policy-name} } in

Syntax Description


prefix-list	IP Version 4 (IPv4) or IP Version 6 (IPv6) prefix list. The list defines which prefixes are to be installed and which are to be omitted when installing routes in the RIB.
route-policy	Specifies the route-policy to filter IS-IS routes.
in	Applies the prefix list or route-policy to incoming routing updates.

Command Default

All routes computed by IS-IS are installed in the RIB.

Command Modes

IS-IS router address-family

Command History


Release	Modification
Release 6.5.1	This command was introduced.

Usage Guidelines

When distribute-list in command is configured, some routes that IS-IS computes are not installed in the forwarding plane of the local router, but other IS-IS routers will not be aware of this. This introduces a difference between the forwarding state computed by other IS-IS routers and the actual forwarding state on this router. In some cases, this could lead to traffic being dropped or looped. Hence, be careful about when to use this command.

Task ID


Task ID	Operation
isis	read, write

Examples

The following example shows how to filter the incoming IS-IS updates using prefix lists:

ipv6 prefix-list v6-1
 10 deny 2020:1000::101/128
 20 permit ::/0 le 128
!
ipv4 prefix-list v4-1
 10 deny 20.1.0.101/32
 20 permit 0.0.0.0/0 le 32
!
router isis 1
 net 49.0001.0000.0000.0100.00
 address-family ipv4 unicast
  metric-style wide
  distribute-list prefix-list v4-1 in
 !
 address-family ipv6 unicast
  metric-style wide
  distribute-list prefix-list v6-1 in
 !

The following example shows how to filter the incoming IS-IS updates using a route-policy for both IPv4 and IPv6:

prefix-set isis-ps-1
  2020:1000::101/128 le 128,
  20.1.0.101/32 le 32
end-set
!
route-policy isis-rp-1
  if destination in isis-ps-1 then
    drop
  elseif tag eq 0 then
    pass
  elseif tag le 100 then
    drop
  else
    pass
  endif
end-policy
!
router isis 1
 net 49.0001.0000.0000.0100.00
 address-family ipv4 unicast
  metric-style wide
  distribute-list route-policy isis-rp-1 in
 !
 address-family ipv6 unicast
  metric-style wide
  distribute-list route-policy isis-rp-1 in
 !

fast-reroute per-link (IS-IS)

To enable IP fast reroute (IPFRR) loop-free alternate (LFA) prefix independent per-link computation, use the fast-reroute per-link command in interface address family configuration mode. To disable this feature, use the no form of this command.

fast-reroute per-link [exclude interface type interface-path-id | level {1 | 2} | lfa-candidate interface type interface-path-id]

no fast-reroute per-link

Syntax Description

exclude

Specifies fast-reroute (FRR ) loop-free alternate (LFA) computation exclusion information

level {1 | 2}

Configures FRR LFA computation for one level only.

lfa-candidate

Specifies FRR LFA computation candidate information

interface

Specifies an interface that needs to be either excluded from FRR LFA computation (when used with exclude keyword) or to be included to LFA candidate list in FRR LFA computation (when used with the lfa-candidate keyword).

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

Command Default

IP fast-reroute LFA per-link computation is disabled.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 4.0.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to configure per-link fast-reroute LFA computation for the IPv4 unicast topology at Level 1:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-if-af)# fast-reroute per-link level 1

fast-reroute per-prefix (IS-IS)

To enable IP fast reroute (IPFRR) loop-free alternate (LFA) prefix dependent computation, use the fast-reroute per-prefix command in interface address family configuration mode. LFA is supported only on Enhanced Ethernet line card.

fast-reroute per-prefix [exclude interface type interface-path-id | level {1 | 2} | lfa-candidate interface type interface-path-id | | remote-lfa {maximum-metric metric-value | tunnel mpls-ldp} prefix-listprefix-list-name [level {1 | 2}]]

Syntax Description

exclude

Specifies fast-reroute (FRR ) loop-free alternate (LFA) computation exclusion information

level {1 | 2}

Configures FRR LFA computation for one level only.

lfa-candidate

Specifies FRR LFA computation candidate information

interface

Specifies an interface that needs to be either excluded from FRR LFA computation (when used with exclude keyword) or to be included to LFA candidate list in FRR LFA computation (when used with the lfa-candidate keyword).

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

remote-lfa

Enable remote LFA related configuration.

prefix-list prefix-list-name

Filter PQ node router ID based on prefix list.

Command Default

IP fast-reroute LFA per-prefix computation is disabled.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 6.0	This command was introduced.

Usage Guidelines

No specific guidelines impact the use of this command.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to configure per-prefix fast-reroute LFA computation for the IPv4 unicast topology at Level 1:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0 
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-if-af)# fast-reroute per-prefix level 1

Examples

This example shows how to configure per-prefix remote-lfa prefix list. The prefix-list option filters PQ node router ID based on prefix list.

RP/0/RP0/CPU0:router(config-isis-af)# fast-reroute per-prefix remote-lfa prefix-list

fast-reroute per-link priority-limit (IS-IS)

To enable the IP fast reroute (IPFRR) loop-free alternate (LFA) prefix independent per-link computation, use the fast-reroute per-link priority-limit command in address family configuration mode. To disable this feature, use the no form of this command.

fast-reroute per-link priority-limit {critical | high | medium} level {1 | 2}

no fast-reroute per-link priority-limit

Syntax Description


critical	Enables LFA omputation for critical priority prefixes only.
high	Enables LFA computation for for criticaland high priority prefixes.
medium	Enables LFA computation for for critical, high, and medium priority prefixes.
level {1\|2}	Sets priority-limit for routing Level 1 or Level 2 independently.

Command Default

Fast-reroute per link priority limit LFA computation is disabled.

Command Modes

IPv4 unicast address family configuration

IPv6 unicast address family configuration

IPv4 multicast address family configuration

IPv6 multicast address family configuration

Command History


Release	Modification
Release 4.0.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

This example shows how to configure fast-reroute prefix independent per-link computation for critical priority prefixes for level 1 only:


RP/0/RSP0/CPU0:router#configure 
RP/0/RSP0/CPU0:router(config)#router isis isp_lfa
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-link priority-limit critical level 1

fast-reroute per-link use-candidate-only (IS-IS)

To exclude all interfaces by default from prefix independent per-link fast-reroute computation, use the fast-reroute per-link use-candidate-only command ISIS address family configuration mode. To include all interfaces by default, use the no form of this command.

fast-reroute per-link use-candidate-only [level {1 | 2}]

no fast-reroute per-link use-candidate-only

Syntax Description


level {1 \| 2}	[Optional] Sets priority-limit for routing Level 1 or Level 2 independently.

Command Default

None

Command Modes

IPv4 unicast address family configuration

IPv6 unicast address family configuration

IPv4 multicast address family configuration

IPv6 multicast address family configuration

Command History


Release	Modification
Release 4.2.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

This command can be configured for a specific level. If no level is given it is applicable for both level 1 and level 2.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to configure the fast-reroute per-link use-candidate-only command for Level 1.

RP/0/RSP0/CPU0:router#configure
RP/0/RSP0/CPU0:router(config)#router isis isp
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute use-candidate-only per-link level 1

fast-reroute per-prefix load-sharing disable (IS-IS)

To disable load sharing prefixes across multiple backups, use the fast-reroute per-prefix load-sharing disable command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.

fast-reroute per-prefix load-sharing disable

no fast-reroute per-prefix load-sharing disable

Syntax Description


level {1\|2}	Disables load-sharing for Level 1 or Level 2 independently.

Command Default

Load sharing is enabled.

Command Modes

IPv4 unicast address family configuration

IPv4 multicast address family configuration

Command History


Release	Modification
Release 4.0.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

This example shows how to disable load-sharing prefixes across multiple backups for level 1 routes:


RP/0/RSP0/CPU0:router#configure
RP/0/RSP0/CPU0:router(config)#router isis isp_lfa
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix load-sharing disable level 1

fast-reroute per-prefix tiebreaker (IS-IS)

To configure tie-breaker for multiple backups, use the fast-reroute per-prefix tiebreaker command in IPv4 address family configuration mode. To disable tie-breaker configuration, use the no form of this command.

fast-reroute per-prefix tiebreaker [downstream | lc-disjoint | lowest-backup-metric | node-protecting | primary-path | secondary-path| srlg-disjoint index] index index_number level {1 | 2}no fast-reroute per-prefix tiebreaker

Syntax Description


downstream	Configures to prefer backup path via downstream node, in case of tie-breaker.
lc-disjoint	Configures to prefer Prefer line card disjoint backup path.
lowest-backup-metric	Configures to prefer backup path with lowest total metric.
node-protecting	Configures to prefer node protecting backup path.
primary-path	Configures to prefer backup path from ECMP set.
secondary-path	Configures to prefer non-ECMP backup path.
srlg-disjoint	Configures to prefer srlg disjoint backup path.
index	Sets preference order among tie-breakers.
`index_number`	Value for the index. Range is 1-255.
level {1 \| 2}	Configures tiebreaker for Level 1 or Level 2 independently.

Command Default

Tie-breaker for multiple backups is not configured.

Command Modes

IPv4 unicast address family configuration

IPv4 multicast address family configuration

Command History


Release	Modification
Release 4.0.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

This example shows how to configure preference of backup path via downstream node in case of a tie-breaker for selection of backup path from multiple backup paths:


RP/0/RSP0/CPU0:router#configure
RP/0/RSP0/CPU0:router(config)#router isis isp_lfa
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker downstream index 255

Examples

This example shows how to configure all the criterions for backup path selection:


RP/0/RSP0/CPU0:router#configure
RP/0/RSP0/CPU0:router(config)#router isis isp_lfa
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker srlg-disjoint index 10
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker primary-path index 20
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker lowest-backup-metric index 30
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker lc-disjoint index 40
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker node-protecting index 50

fast-reroute per-prefix use-candidate-only (IS-IS)

To exclude all interfaces by default from prefix dependent fast-reroute computation, use the fast-reroute per-prefix use-candidate-only command ISIS address family configuration mode. To include all interfaces by default, use the no form of this command.

fast-reroute per-prefix use-candidate-only [level {1 | 2}]

no fast-reroute per-prefix use-candidate-only

Syntax Description


level {1 \| 2}	[Optional] Sets priority-limit for routing Level 1 or Level 2 independently.

Command Default

None

Command Modes

IPv4 unicast address family configuration

IPv6 unicast address family configuration

IPv4 multicast address family configuration

IPv6 multicast address family configuration

Command History


Release	Modification
Release 4.2.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

This command can be configured for a specific level. If no level is given it is applicable for both level 1 and level 2.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to configure the fast-reroute per-prefix use-candidate-only command for Level 1.

RP/0/RSP0/CPU0:router#configure
RP/0/RSP0/CPU0:router(config)#router isis isp
RP/0/RSP0/CPU0:router(config-isis)#address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-af)#fast-reroute use-candidate-only per-link level 1

hello-interval (IS-IS)

To specify the length of time between consecutive hello packets sent by the Intermediate System-to-Intermediate System (IS-IS) protocol software, use the hello-interval command in interface configuration mode. To restore the default value, use the no form of this command.

hello-interval seconds [level {1 | 2}]

no hello-interval [seconds] [level {1 | 2}]

Syntax Description


`seconds`	Integer value (in seconds) for the length of time between consecutive hello packets. By default, a value three times the hello interval seconds is advertised as the `hold time` in the hello packets sent. (That multiplier of three can be changed by using the hello-multiplier command.) With smaller hello intervals, topological changes are detected more quickly, but there is more routing traffic. Range is 1 to 65535 seconds.
level { 1 \| 2 }	(Optional) Specifies the hello interval for Level 1 and Level 2 independently. For broadcast interfaces only.

Command Default

seconds : 10 seconds

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The hello interval can be configured independently for Level 1 and Level 2, except on serial point-to-point interfaces. (Because only a single type of hello packet is sent on serial links, it is independent of Level 1 or Level 2.) Configuring Level 1 and Level 2 independently is used on LAN interfaces.

Note

A shorter hello interval gives quicker convergence, but increases bandwidth and CPU usage. It might also add to instability in the network.

A slower hello interval saves bandwidth and CPU. Especially when used in combination with a higher hello multiplier, this strategy may increase overall network stability.

For point-to-point links, IS-IS sends only a single hello for Level 1 and Level 2, making the level keyword meaningless on point-to-point links. To modify hello parameters for a point-to-point interface, omit the level keyword.

Note

Currently, a user can configure an aggressive hello-interval (lower than the default of 10 seconds for peer-to-peer session). But, if NSR or NSF is configured, the default hello interval has to be used so that the sessions do not run into the risk of flapping during switchover.

Using LAN adjacencies in high availability (HA) scenarios is not recommended, since there is no designated intermediate system (DIS) redundancy in the protocol and traffic will either drop or be rerouted temporarily during DIS re-election.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure TenGigE interface 0/6/0/0 to advertise hello packets every 5 seconds for Level 1 topology routes. This situation causes more traffic than configuring a longer interval, but topological changes are detected more quickly.


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface TenGigE 0/6/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# hello-interval 5 level 1

Related Commands


Command	Description
hello-multiplier	Specifies the number of IS-IS hello packets a neighbor must miss before the router should declare the adjacency as down.

hello-multiplier

To specify the number of Intermediate System-to-Intermediate System (IS-IS) hello packets a neighbor must miss before the router should declare the adjacency as down, use the hello-multiplier command in interface configuration mode. To restore the default value, use the no form of this command.

hello-multiplier multiplier [level {1 | 2}]

no hello-multiplier [multiplier] [level {1 | 2}]

Syntax Description


`multiplier`	Advertised hold time in IS-IS hello packets is set to the hello multiplier times the hello interval. Range is 3 to 1000. Neighbors declare an adjacency to this down router after not having received any IS-IS hello packets during the advertised hold time. The hold time (and thus the hello multiplier and the hello interval) can be set on an individual interface basis, and can be different between different networking devices in one area. Using a smaller hello multiplier gives faster convergence, but can result in more routing instability. Increase the hello multiplier to a larger value to help network stability when needed. Never configure a hello multiplier to a value lower than the default value of 3.
level { 1 \| 2 }	(Optional) Specifies the hello multiplier independently for Level 1 or Level 2 adjacencies.

Command Default

multiplier : 3

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The “holding time” carried in an IS-IS hello packet determines how long a neighbor waits for another hello packet before declaring the neighbor to be down. This time determines how quickly a failed link or neighbor is detected so that routes can be recalculated.

Use the hello-multiplier command in circumstances where hello packets are lost frequently and IS-IS adjacencies are failing unnecessarily. You can raise the hello multiplier and lower the hello interval (hello-interval (IS-IS) command) correspondingly to make the hello protocol more reliable without increasing the time required to detect a link failure.

On point-to-point links, there is only one hello for both Level 1 and Level 2. Separate Level 1 and Level 2 hello packets are also sent over nonbroadcast multiaccess (NBMA) networks in multipoint mode, such as X.25, Frame Relay, and ATM.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how the network administrator wants to increase network stability by making sure an adjacency goes down only when many (ten) hello packets are missed. The total time to detect link failure is 60 seconds. This strategy ensures that the network remains stable, even when the link is fully congested.


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet /2/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# hello-interval 6
  RP/0/RSP0/CPU0:router(config-isis-if)# hello-multiplier 10

Related Commands


Command	Description
hello-interval (IS-IS)	Specifies the length of time between hello packets that the software sends.

hello-padding

To configure padding on Intermediate System-to-Intermediate System (IS-IS) hello protocol data units (IIH PDUs) for all IS-IS interfaces on the router, use the hello-padding command in interface configuration mode. To suppress padding, use the no form of this command.

hello-padding {disable | sometimes} [level {1 | 2}]

no hello-padding {disable | sometimes} [level {1 | 2}]

Syntax Description


disable	Suppresses hello padding.
sometimes	Enables hello padding during adjacency formation only.
level { 1 \| 2 }	(Optional) Specifies hello padding for Level 1 or Level 2 independently.

Command Default

Hello padding is enabled.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

You might want to suppress hello padding to conserve network resources. The lower the circuit speed, the higher the percentage of padding overhead. Before suppressing the hello padding, you should know your physical and data link layer configurations and have control over them, and also know your router configuration at the network layer.

For point-to-point links, IS-IS sends only a single hello for Level 1 and Level 2, making the level keyword meaningless on point-to-point links. To modify hello parameters for a point-to-point interface, omit the level keyword.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to suppress IS-IS hello padding over local area network (LAN) circuits for interface GigabitEthernet 0/2/0/1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# hello-padding disable

Related Commands


Command	Description
show isis interface	Displays information about the IS-IS interface.

hello-password

To configure the authentication password for an Intermediate System-to-Intermediate System (IS-IS) interface, use the hello-password command in interface configuration mode. To disable authentication, use the no form of this command.

hello-password [hmac-md5 | text] [clear | encrypted] password [level {1 | 2}] [send-only]

no hello-password [hmac-md5 | text] [clear | encrypted] password [level {1 | 2}] [send-only]

Syntax Description


hmac-md5	(Optional) Specifies that the password use HMAC-MD5 authentication.
text	(Optional) Specifies that the password use clear text password authentication.
clear	(Optional) Specifies that the password be unencrypted.
encrypted	(Optional) Specifies that the password be encrypted using a two-way algorithm.
`password`	Authentication password you assign for an interface.
level { 1 \| 2 }	(Optional) Specifies whether the password is for a Level 1 or a Level 2 protocol data unit (PDU).
send-only	(Optional) Specifies that the password applies only to protocol data units (PDUs) that are being sent and does not apply to PDUs that are being received.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

password: encrypted text

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

When a text password is configured, it is exchanged as clear text. Therefore, the hello-password command provides limited security.

When an hmac-md5 password is configured, the password is never sent over the network and is instead used to calculate a cryptographic checksum to ensure the integrity of the exchanged data.

For point-to-point links, IS-IS sends only a single hello for Level 1 and Level 2, making the level keyword meaningless on point-to-point links. To modify hello parameters for a point-to-point interface, omit the level keyword.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a password with HMAC-MD5 authentication for hello packets running on GigabitEthernet 0/2/0/3 interface:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/3
  RP/0/RSP0/CPU0:router(config-isis-if)# hello-password hmac-md5 clear mypassword

Related Commands


Command	Description
hello-password keychain	Configures the authentication password keychain for an Intermediate System-to-Intermediate System (IS-IS) interface.
hello-password accept	Configures an additional authentication password for an IS-IS interface.

hello-password keychain

To configure the authentication password keychain for an Intermediate System-to-Intermediate System (IS-IS) interface, use the hello-password keychain command in interface configuration mode. To disable the authentication password keychain, use the no form of this command.

hello-password keychain keychain-name [level {1 | 2}] [send-only]

no hello-password keychain keychain-name [level {1 | 2}] [send-only]

Syntax Description


keychain	Keyword that specifies the keychain to be configured. An authentication password keychain is a sequence of keys that are collectively managed and used for authenticating a peer-to-peer group.
`keychain-name`	Specifies the name of the keychain.
level { 1 \| 2 }	(Optional) Specifies whether the keychain is for a Level 1 or a Level 2 protocol data unit (PDU).
send-only	(Optional) Specifies that the keychain applies only to protocol data units (PDUs) that are being sent and does not apply to PDUs that are being received.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

password: encrypted text

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Specify a keychain to enable keychain authentication between two IS-IS peers. Use the keychain keychain-name keyword and argument to implement hitless key rollover for authentication.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a password keychain for level 1, send only authentication on a GigabitEthernet interface:


  RP/0/RSP0/CPU0:routerRP/0/RSP0/CPU0:router(config)# router isis isp 
  RP/0/RSP0/CPU0:routerRP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/0 
  RP/0/RSP0/CPU0:routerRP/0/RSP0/CPU0:router(config-isis-if)# hello-password keychain mykeychain level 1 send-only

Related Commands


Command	Description
hello-password	Configures the authentication password for an Intermediate System-to-Intermediate System (IS-IS) interface.
hello-password accept	Configures an additional authentication password for an IS-IS interface.

hello-password accept

To configure an additional authentication password for an Intermediate System-to-Intermediate System (IS-IS) interface, use the hello-password accept command in interface configuration mode. To disable authentication, use the no form of this command.

hello-password accept {clear | encrypted} password [level {1 | 2}]

no hello-password accept {clear | encrypted} password [level {1 | 2}]

Syntax Description


clear	Specifies that the password be unencrypted.
encrypted	Specifies that the password be encrypted using a two-way algorithm.
`password`	Authentication password you assign.
level { 1 \| 2 }	(Optional) Specifies the password for Level 1 or Level 2 independently.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the hello-password accept command to add an additional password for an IS-IS interface. An authentication password must be configured using the hello-password command before an accept password can be configured for the corresponding level.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a password:


  RP/0/RSP0/CPU0:routerRP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:routerRP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/3
  RP/0/RSP0/CPU0:routerRP/0/RSP0/CPU0:router(config-isis)# hello-password accept encrypted 111D1C1603

Related Commands


Command	Description
hello-password	Configures an authentication password for an IS-IS interface.

hostname dynamic disable

To disable Intermediate System-to-Intermediate System (IS-IS) routing protocol dynamic hostname mapping, use the hostname dynamic command in router configuration mode. To remove the specified command from the configuration file and restore the system to its default condition, use the no form of this command.

hostname dynamic disable

no hostname dynamic disable

Syntax Description


disable	Disables dynamic host naming.

Command Default

Router names are dynamically mapped to system IDs.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

In an IS-IS routing domain, each router is represented by a 6-byte hexadecimal system ID. When network administrators maintain and troubleshoot networking devices, they must know the router name and corresponding system ID.

Link-state packets (LSPs) include the dynamic hostname in the type, length, and value (TLV) which carries the mapping information across the entire domain. Every router in the network, upon receiving the TLV from an LSP, tries to install it in a mapping table. The router then uses the mapping table when it wants to convert a system ID to a router name.

To display the entries in the mapping tables, use the show isis hostname command.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to disable dynamic mapping of hostnames to system IDs:


 RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# hostname dynamic disable

Related Commands


Command	Description
hostname	Specifies the name of the local router.
show isis hostname	Displays the router name-to-system ID mapping table.

ignore-lsp-errors

To override the default setting of a router to ignore Intermediate System-to-Intermediate System (IS-IS) link-state packets (LSPs) that are received with internal checksum errors, use the ignore-lsp-errors disable command in router configuration mode. To enable ignoring IS-IS LSP errors, use the no form of this command.

ignore-lsp-errors disable

no ignore-lsp-errors disable

Syntax Description


disable	Disables the functionality of the command.

Command Default

The system ignores corrupt LSPs.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The IS-IS protocol definition requires that a received LSP with an incorrect data-link checksum be purged by the receiver, which causes the initiator of the packet to regenerate it. However, if a network has a link that causes data corruption and at the same time is delivering LSPs with correct data-link checksums, a continuous cycle of purging and regenerating large numbers of packets can occur. Because this situation could render the network nonfunctional, use this command to ignore these LSPs rather than purge the packets.

The receiving network devices use link-state packets to maintain their routing tables.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to instruct the router to purge LSPs that cause the initiator to regenerate LSPs:


 RP/0/RSP0/CPU0:router(config)# router isis isp
 RP/0/RSP0/CPU0:router(config-isis)# ignore-lsp-errors disable

instance-id

To allow a router to share one or more circuits among multiple Intermediate System to Intermediate System (IS-IS) routing protocol instances, use the instance-id command in router configuration mode.

instance-id identifier

Syntax Description


`identifier`	Specifies the Intermediate System to Intermediate System (IS-IS) routing protocol instance. Range is 1-65535.

Command Default

Disabled

Command Modes

Router configuration

Command History


Release	Modification
Release 6.1.x	This command was introduced.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure multiple instances on a single router:


  RP/0/RSP0/CPU0:router(config)# router isis ring
  RP/0/RSP0/CPU0:router(config-isis)# instance-id 1 
  RP/0/RSP0/CPU0:router(config-isis)# exit
  RP/0/RSP0/CPU0:router(config)# router isis 1
  RP/0/RSP0/CPU0:router(config-isis)# instance-id 6 
  RP/0/RSP0/CPU0:router(config-isis)#

interface (IS-IS)

To configure the Intermediate System-to-Intermediate System (IS-IS) protocol on an interface, use the interface command in router configuration mode. To disable IS-IS routing for interfaces, use the no form of this command.

interface type interface-path-id

no interface type interface-path-id

Syntax Description

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

Command Default

No interfaces are specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

An address family must be established on the IS-IS interface before the interface is enabled for IS-IS protocol operation.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable an IS-IS multitopology configuration for IPv4 on GigabitEthernet interface 0/3/0/0:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# net 49.0000.0000.0001.00
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-if-af)# metric-style wide level 1
  !
  RP/0/RSP0/CPU0:router(config)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-if)# ipv4 address 2001::1/64

Related Commands


Command	Description
log adjacency changes (IS-IS)	Configures the routing level for an instance of the IS-IS routing process.
net	Configures an IS-IS network entity title (NET) for the routing process.
router isis	Enables the IS-IS routing protocol.

ipfrr lfa

The ipfrr lfa commands are deprecated in Release 4.0.1, and replaced with the fast-reroute commands. For more information, see the following:

fast-reroute per-link priority-limit [level <1-2>]

fast-reroute per-prefix priority-limit [level <1-2>]

fast-reroute per-prefix tiebreaker index <1-255> [level <1-2>]

fast-reroute per-prefix load-sharing disable [level <1-2>]

fast-reroute [level <1-2>]

fast-reroute per-link exclude interface [level <1-2>]

fast-reroute per-link lfa-candidate interface [level <1-2>]

fast-reroute per-prefix exclude interface [level <1-2>]

fast-reroute per-prefix lfa-candidate interface [level <1-2>]

show isis fast-reroute summary

show isis fast-reroute [prefix] [longer-prefixes]

show isis fast-reroute detail [prefix] [longer-prefixes]

To enable the IP fast reroute (IPFRR) loop-free alternate (LFA) computation, use the ipfrr lfa command in interface address family configuration mode. To disable this feature, use the no form of this command.

ipfrr lfa level {1 | 2}

no ipfrr lfa level {1 | 2}

Syntax Description


level { 1 \| 2 }	Configures IPFRR LFA for Level 1 or Level 2 independently.

Command Default

IPFRR LFA is disabled.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 3.9.0	This command was introduced.
Release 4.0.1	This command was deprecated and replaced with the fast-reroute commands.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the ipfrr lfa command to compute loop-free alternates for all links or neighbors in the event of a link failure.

To enable node protection on broadcast links, IPRR and bidirectional forwarding detection (BFD) must be enabled on the interface under IS-IS. See Cisco IOS XR Interface and Hardware Configuration Guide for information on configuring BFD.

Note

Multiprotocol Label Switching (MPLS) FRR and IPFRR cannot be configured on the same interface simultaneously.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure IPFRR for the IPv4 unicast topology at Level 1:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-if-af)# ipfrr lfa level 1

ipfrr lfa exclude interface

To exclude an interface from the IP fast reroute (IPFRR) loop-free alternate (LFA) computation, use the ipfrr lfa exclude interface command in interface address family configuration mode. To disable this feature, use the no form of this command.

ipfrr lfa exclude interface type interface-path-id

no ipfrr lfa exclude interface type interface-path-id

Syntax Description

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

IPFRR LFA is disabled.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 3.9.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the ipfrr lfa command to compute loop-free alternates for all links or neighbors in the event of a link failure.

To enable node protection on broadcast links, IPRR and bidirectional forwarding detection (BFD) must be enabled on the interface under IS-IS. See Cisco IOS XR Interface and Hardware Configuration Guide for information on configuring BFD.

Note

Multiprotocol Label Switching (MPLS) FRR and IPFRR cannot be configured on the same interface simultaneously.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure to exclude 0/1/0/0 interface from IPFRR LFA:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/0
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-if-af)# ipfrr lfa exclude interface GigabitEthernet 0/1/0/0

Related Commands


Command	Description
ipfrr lfa	Enable the IP fast reroute (IPFRR) loop-free alternate (LFA) computation

ispf

To configure the incremental shortest path first (iSPF) algorithm to calculate network topology, use the ispf command in address family configuration mode. To disable this algorithm function, use the no form of this command.

ispf [level {1 | 2}]

no ispf [level {1 | 2}]

Syntax Description


level { 1 \| 2 }	(Optional) Configures the iSPF algorithm for Level 1 or Level 2 independently.

Command Default

The iSPF algorithm is not configured.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The iSPF algorithm may be used to reduce the processor load when IS-IS needs to recalculate its topology after minor changes.

Note

The incremental shortest path first (ISPF) algorithm was developed to improve SPF performance in the days of slow CPUs and before more advanced technological solutions like Fast Re-Route (FRR) and micro-loop avoidance were available. FRR and micro-loop avoidance both depend on information that is computed during a full SPF calculation and saved in the resulting shortest path tree.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure iSPF for the IPv4 unicast topology at Level 1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# ispf level 1

is-type

To configure the routing level for an Intermediate System-to-Intermediate System (IS-IS) area, use the is-type command in router configuration mode. To set the routing level to the default level, use the no form of this command.

is-type {level-1 | level-1-2 | level-2-only}

no is-type [level-1 | level-1-2 | level-2-only]

Syntax Description


level-1	Specifies that the router perform only Level 1 (intra-area) routing. This router learns only about destinations inside its area. Level 2 (interarea) routing is performed by the closest Level 1-2 router.
level-1-2	Specifies that the router perform both Level 1 and Level 2 routing.
level-2-only	Specifies that the routing process acts as a Level 2 (interarea) router only. This router is part of the backbone, and does not communicate with Level 1-only routers in its own area.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

When the router is configured with Level 1 routing only, this router learns about destinations only inside its area. Level 2 (interarea) routing is performed by the closest Level 1-2 router.

When the router is configured with Level 2 routing only, this router is part of the backbone, and does not communicate with Level 1 routers in its own area.

The router has one link-state packet database (LSDB) for destinations inside the area (Level 1 routing) and runs a shortest path first (SPF) calculation to discover the area topology. It also has another LSDB with link-state packets (LSPs) of all other backbone (Level 2) routers, and runs another SPF calculation to discover the topology of the backbone and the existence of all other areas.

We highly recommend that you configure the type of an IS-IS routing process to establish the proper level of adjacencies. If there is only one area in the network, there is no need to run both Level 1 and Level 2 routing algorithms.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to specify that the router is part of the backbone and that it does not communicate with Level 1-only routers:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# is-type level-2-only

Related Commands


Command	Description
circuit-type	Configures the type of adjacency.
show isis neighbors	Displays information about IS-IS neighbors.

link-down fast-detect

To enable fast detection of link down events under ISIS, use the link-down fast-detect command in ISIS interface configuration mode.

link-down fast-detect

Syntax Description

This command has no arguments or keywords.

Command Default

Fast detect is not enabled.

Command Modes

ISIS interface configuration.

Command History


Release	Modification
Release 3.9.1	This command was introduced.

Examples

The following example shows how to enable fast detection of link down events under ISIS:


  RP/0/RP0/CPU0:router(config)# router isis isp
  RP/0/RP0/CPU0:router(config-isis)# interface HundredGigE0/3/0/2 
  RP/0/RP0/CPU0:router(config-isis-if)# link-down fast-detect

link-group

To configure an interface as a member of a link group, use the link-group command in the IS-IS interface or address-family configuration mode. To remove an interface from a link-group, use the no form of this command.

link-group link-group-name

no link-group link-group-name

Syntax Description


`link-group-name`	Name of a link group.

Command Default

No link groups are configured.

Command Modes

IS-IS interface configuration

Address-family configuration

Command History


Release	Modification
Release 4.3.1	This command was introduced.

Usage Guidelines

One IS-IS interface and address-family can specify only one link-group association. The default is for both levels regardless of current circuit-type. The link-group association can be specified for one level only if configured.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure GigabitEthernet interface 0/3/0/0 as a member of a link group:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-if-af)# link-group purple

log adjacency changes (IS-IS)

To cause an IS-IS instance to generate a log message when an Intermediate System-to-Intermediate System (IS-IS) adjacency changes state (up or down), use the log adjacency changes command in router configuration mode. To restore the default value, use the no form of this command.

log adjacency changes

no log adjacency changes

Command Default

No IS-IS instance log messages are generated.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

Use the log adjacency changes command to monitor IS-IS adjacency state changes; it may be very useful when you are monitoring large networks. Messages are logged using the system error message facility. Messages can be in either of two forms:


  %ISIS-4-ADJCHANGE: Adjacency to 0001.0000.0008 (Gi 0/2/1/0) (L2) Up, new adjacency
  %ISIS-4-ADJCHANGE: Adjacency to router-gsr8 (Gi /2/1/0) (L1) Down, Holdtime expired

Using the no form of the command removes the specified command from the configuration file and restores the system to its default condition with respect to the command.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the router to log adjacency changes:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# log adjacency changes

Related Commands


Command	Description
logging	Logs messages to a syslog server host.

log pdu drops

To log Intermediate System-to-Intermediate System (IS-IS) protocol data units (PDUs) that are dropped, use the log pdu drops command in router configuration mode. To disable this function, use the no form of this command.

log pdu drops

no log pdu drops

Command Default

PDU logging is disabled.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the log pdu drops command to monitor a network when IS-IS PDUs are suspected of being dropped. The reason for the PDU being dropped and current PDU drop statistics are recorded.

The following are examples of PDU logging output:


%ISIS-4-ERR_LSP_INPUT_Q_OVERFLOW - An incoming LSP or SNP pdu was dropped because the input queue was full
%ISIS-3-ERR_SEND_PAK - The process encountered a software-error while sending the IS-IS packet

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable PDU logging:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# log pdu drops

lsp fast-flood threshold

To configure the link-state packet (LSP) fast-flood threshold, use the lsp fast-flood threshold command in interface configuration mode. To restore the default value, use the no form of this command.

lsp fast-flood threshold lsp-number [level {1 | 2}]

no lsp fast-flood threshold [lsp-number] [level {1 | 2}]

Syntax Description


`lsp-number`	Number of LSPs to send back to back. Range is 1 to 4294967295.
level { 1 \| 2 }	(Optional) Specifies the LSP threshold for Level 1 or Level 2 independently.

Command Default

10 LSPs are allowed in a back-to-back window

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the lsp fast-flood threshold command to accelerate convergence of LSP database. LSPs are sent back-to-back over an interface up to the specified limit. Past the limit, LSPs are sent out in the next batch window as determined by LSP pacing interval.

Duration of back-to-back window = LSP interval * LSP fast-flood threshold limit.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the LSP threshold:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# lsp fast-flood threshold 234 level 1

Related Commands


Command	Description
lsp-interval	Configures the amount of time between consecutive LSPs sent on an IS-IS interface.

lsp-fast-flooding

To enable the fast flooding of Link State Packets (LSPs) to improve network response to topology changes, use the lsp-fast-flooding command in IS-IS router configuration mode.

lsp-fast-flooding [ max-lsp-tx lsps-per-sec | remote-psnp-delay milliseconds\

Syntax Description


max-lsp-tx `lsps-per-sec`	(Optional) Sets the maximum number of LSPs that can be transmitted per second. The default is 1000. The range is from 33 through 5000
remote-psnp-delay `milliseconds`	(Optional) Specifies the maximum delay, in milliseconds, that the router should wait for a PSNP acknowledgment from neighbors after sending an LSP. The default is 500 ms. The range is from 1 through 5000 ms.

Command Default

This command is disabled by default. IS-IS fast flooding of LSPs is not enabled.

Command Modes

Router configuration

Command History


Release	Modification
Release 24.3.1	This command was introduced.

Usage Guidelines

None.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to enable IS-IS fast flooding of LSPs.

Router# configure terminal
Router(config)# router isis 1
Router(config-router)# lsp-fast-flooding

This example shows how to set the maximum LSP transmission rate to 600 LSPs per second.

Router# configure terminal
Router(config)# router isis 1
Router(config-router)# lsp-fast-flooding
Router(config-isis-lsp-fast-flooding)# max-lsp-tx 600

This example shows how to set the PSNP acknowledgment delay to 600 milliseconds.

Router# configure terminal
Router(config)# router isis 1
Router(config-router)# lsp-fast-flooding
Router(config-isis-lsp-fast-flooding)# remote-psnp-delay 600

lsp-gen-interval

To customize IS-IS throttling of link-state packet (LSP) generation, use the lsp-gen-interval command in router configuration mode. To restore the default value, use the no form of this command.

lsp-gen-interval [initial-wait initial] [secondary-wait secondary] [maximum-wait maximum] [level {1 | 2}]

no lsp-gen-interval [ [initial-wait initial] [secondary-wait secondary] [maximum-wait maximum]] [level {1 | 2}]

Syntax Description


initial-wait `initial`	Specifies the initial LSP generation delay (in milliseconds). Range is 0 to 120000 milliseconds.
secondary-wait `secondary`	Specifies the hold time between the first and second LSP generation (in milliseconds). Range is 1 to 120000 milliseconds.
maximum-wait `maximum`	Specifies the maximum interval (in milliseconds) between two consecutive occurrences of an LSP being generated. Range is 1 to 120000 milliseconds.
level { 1 \| 2 }	(Optional) Specifies the LSP time interval for Level 1 or Level 2 independently.

Command Default

initial-wait initial : 50 milliseconds

secondary-wait secondary : 200 milliseconds

maximum-wait maximum : 5000 milliseconds

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

During prolonged periods of network instability, repeated recalculation of LSPs can cause increased CPU load on the local router. Further, the flooding of these recalculated LSPs to the other Intermediate Systems in the network causes increased traffic and can result in other routers having to spend more time running route calculations.

Use the lsp-gen-interval command to reduce the rate of LSP generation during periods of instability in the network. This command can help to reduce CPU load on the router and to reduce the number of LSP transmissions to its IS-IS neighbors.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to set the maximum interval between two consecutive occurrences of an LSP to 15 milliseconds and the initial LSP generation delta to 5 milliseconds:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# lsp-gen-interval maximum-wait 15 initial-wait 5

Related Commands


Command	Description
retransmit-interval (IS-IS)	Configures the amount of time between retransmission of each IS-IS LSP on a point-to-point link.

lsp-interval

To configure the amount of time between consecutive link-state packets (LSPs) sent on an Intermediate System-to-Intermediate System (IS-IS) interface, use the lsp-interval command in interface configuration mode. To restore the default value, use the no form of this command.

lsp-interval milliseconds [level {1 | 2}]

no lsp-interval [milliseconds] [level {1 | 2}]

Syntax Description


`milliseconds`	Time delay (in milliseconds) between successive LSPs. Range is 1 to 4294967295.
level { 1 \| 2 }	(Optional) Configures the LSP time delay for Level 1 or Level 2 independently.

Command Default

milliseconds : 33 milliseconds

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to cause the system to send LSPs every 100 milliseconds (10 packets per second) on Level 1 and Level 2:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet /2/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# lsp-interval 100

Related Commands


Command	Description
retransmit-interval (IS-IS)	Configures the amount of time between retransmission of each IS-IS LSP on a point-to-point link.

lsp-mtu

To set the maximum transmission unit (MTU) size of Intermediate System-to-Intermediate System (IS-IS) link-state packets (LSPs), use the lsp-mtu command in router configuration mode. To restore the default, use the no form of this command.

lsp-mtu bytes [level {1 | 2}]

no lsp-mtu [bytes] [level {1 | 2}]

Syntax Description

bytes

Maximum packet size in bytes. The number of bytes must be less than or equal to the smallest MTU of any link in the network. Range is 128 to 4352 bytes.

Note

Range is 128 to 8979 bytes from Release 6.6.3 onwards.

level { 1 | 2 }

(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.1	The maximum packet size is increased to 8979.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Under normal conditions, the default MTU size should be sufficient. However, if the MTU size of a link is less than 1500 bytes, the LSP MTU size must be lowered accordingly on each router in the network. If this action is not taken, routing becomes unpredictable.

This guideline applies to all Cisco networking devices in a network. If any link in the network has a reduced MTU size, all devices must be changed, not just the devices directly connected to the link.

Note

Do not set the lsp-mtu command (network layer) to a value greater than the link MTU size that is set with the mtu command (physical layer).

To be certain about a link MTU size, use the show isis interface command to display the value.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to set the MTU size to 1300 bytes:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# lsp-mtu 1300

Related Commands


Command	Description
mtu	Adjusts the maximum packet size or MTU size.
show isis interface	Displays information about the IS-IS interface.

lsp-password

To configure the link-state packet (LSP) authentication password, use the lsp-password command in router configuration mode. To remove the lsp-password command from the configuration file and disable link-state packet authentication, use the no form of this command.

lsp-password [ [hmac-md5 | text] [clear | encrypted] password | keychain keychain-name] [level {1 | 2}] [send-only] [snp send-only]]

no lsp-password [ [hmac-md5 | text] [clear | encrypted] password | keychain keychain-name] [level {1 | 2}] [send-only] [snp send-only]]

Syntax Description


hmac-md5	Specifies that the password uses HMAC-MD5 authentication.
text	Specifies that the password uses clear text password authentication.
clear	Specifies that the password be unencrypted.
encrypted	Specifies that the password be encrypted using a two-way algorithm.
`password`	Authentication password you assign.
keychain	(Optional) Specifies a keychain.
`keychain-name`	Name of the keychain.
level { 1 \| 2 }	(Optional) Specifies the password for Level 1 or Level 2 independently.
send-only	(Optional) Adds passwords to LSP and sequence number protocol (SNP) data units when they are sent. Does not check for authentication in received LSPs or sequence number PDUs (SNPs).
snp send-only	(Optional) Adds passwords to SNP data units when they are sent. Does not check for authentication in received SNPs. This option is available when the text keyword is specified.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

When a text password is configured, it is exchanged as clear text. Therefore, the lsp-password command provides limited security.

When an HMAC-MD5 password is configured, the password is never sent over the network and is instead used to calculate a cryptographic checksum to ensure the integrity of the exchanged data.

The recommended password configuration is that both incoming and outgoing SNPs be authenticated.

Note

To disable SNP password checking, the snp send-only keywords must be specified in the lsp-password command.

To configure an additional password, use the lsp-password accept command.

Specify a key chain to enable key chain authentication between two IS-IS peers. Use the keychain keychain-name keyword and argument to implement hitless key rollover for authentication.

If you are performing LSP authentication and want to use the Purge Originator Identification feature, then use the enable-poi keyword in the lsp-password command.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure separate Level 1 and Level 2 LSP and SNP passwords, one with HMAC-MD5 authentication and encryption and one with clear text password authentication and no encryption:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# lsp-password hmac-md5 clear password1 level 1
  RP/0/RSP0/CPU0:router(config-isis)# lsp-password text clear password2 level 2

Related Commands


Command	Description
lsp-password accept	Configures an additional LSP password when one LSP password is already configured for a level.

lsp-password accept

To configure an additional link-state packet (LSP) authentication password, use the lsp-password accept command in router configuration mode. To remove the lsp-password accept command from the configuration file and restore the system to its default condition, use the no form of this command.

lsp-password accept {clear | encrypted} password [level {1 | 2}]

no lsp-password accept [ {clear | encrypted} password [level {1 | 2}]]

Syntax Description


clear	Specifies that the password be unencrypted.
encrypted	Specifies that the password be encrypted using a two-way algorithm.
`password`	Authentication password you assign.
level { 1 \| 2 }	(Optional) Specifies the password for Level 1 or Level 2 independently.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The lsp-password accept command adds an additional password for use when the system validates incoming LSPs and sequence number PDUs (SNPs). An LSP password must be configured using the lsp-password command before an accept password can be configured for the corresponding level.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure an Level 1 LSP and SNP password:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# lsp-password accept encrypted password1 level 1

Related Commands


Command	Description
lsp-password	Configures an authentication LSP password.

lsp-refresh-interval

To set the time between regeneration of link-state packets (LSPs) that contain different sequence numbers, use the lsp-refresh-interval command in router configuration mode. To restore the default refresh interval, use the no form of this command.

lsp-refresh-interval seconds [level {1 | 2}]

no lsp-refresh-interval [seconds [level {1 | 2}]]

Syntax Description


`seconds`	Refresh interval (in seconds). Range is 1 to 65535 seconds.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

seconds : 900 seconds (15 minutes)

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The refresh interval determines the rate at which the software periodically sends the route topology information that it originates. This behavior is done to keep the information from becoming too old. By default, the refresh interval is 900 seconds (15 minutes).

LSPs must be refreshed periodically before their lifetimes expire. The refresh interval must be less than the LSP lifetime specified with this router command. Reducing the refresh interval reduces the amount of time that undetected link-state database corruption can persist at the cost of increased link utilization. (This event is extremely unlikely, however, because there are other safeguards against corruption.) Increasing the interval reduces the link utilization caused by the flooding of refreshed packets (although this utilization is very small).

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to change the LSP refresh interval to 10,800 seconds (3 hours):


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# lsp-refresh-interval 10800

Related Commands


Command	Description
max-lsp-lifetime	Sets the maximum time that LSPs persist without being refreshed.

maximum-paths (IS-IS)

To configure the maximum number of parallel routes that an IP routing protocol will install in the routing table, use the maximum-paths command in address family configuration mode. To remove the maximum-paths command from the configuration file and restore the system default behavior, use the no form of this command. By default up to 8 parallel ECMP paths are used by IS-IS routing protocol.

maximum-paths maximum

no maximum-paths

Syntax Description


`maximum`	Maximum number of parallel routes that IS-IS can install in a routing table. Range is 1 to 64

Command Default

Note

The default value used for maximum-paths is 8.

Command Modes

Address family configuration

Command History


Release	Modification
Release 5.3.0	ECMP support extended from 32 to 64 paths.
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to allow a maximum of 16 paths to a destination:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# maximum-paths 16

maximum-redistributed-prefixes (IS-IS)

To specify an upper limit on the number of redistributed prefixes (subject to summarization) that the Intermediate System-to-Intermediate System (IS-IS) protocol advertises, use the maximum-redistributed-prefixes command in address family mode. To disable this feature, use the no form of this command.

maximum-redistributed-prefixes maximum [level {1 | 2}]

no maximum-redistributed-prefixes [maximum [level {1 | 2}]]

Syntax Description


`maximum`	Maximum number of redistributed prefixes advertised. Range is 1 to 28000.
level { 1 \| 2 }	(Optional) Specifies maximum prefixes for Level 1 or Level 2.

Command Default

maximum: 10000

level : 1-2

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the maximum-redistributed-prefixes command to prevent a misconfiguration from resulting in redistribution of excess prefixes. If IS-IS encounters more than the maximum number of prefixes, it sets a bi-state alarm. If the number of to-be-redistributed prefixes drops back to the maximum or lower—either through reconfiguration or a change in the redistribution source—IS-IS clears the alarm.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to specify the number of redistributed prefixes at 5000 for Level 2:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast 
  RP/0/RSP0/CPU0:router(config-isis-af)# maximum-redistributed-prefixes 5000 level 2

max-lsp-lifetime

To set the maximum time that link-state packets (LSPs) persist without being refreshed, use the max-lsp-lifetime command in router configuration mode. To restore the default time, use the no form of this command.

max-lsp-lifetime seconds [level {1 | 2}]

no max-lsp-lifetime [seconds [level {1 | 2}]]

Syntax Description


`seconds`	Lifetime (in seconds) of the LSP. Range from 1 to 65535 seconds.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

seconds : 1200 seconds (20 minutes)

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

You might need to adjust the maximum LSP lifetime if you change the LSP refresh interval with the lsp-refresh-interval command. The maximum LSP lifetime must be greater than the LSP refresh interval.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to set the maximum time that the LSP persists to 11,000 seconds (more than 3 hours):


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# max-lsp-lifetime 11000

Related Commands


Command	Description
lsp-refresh-interval	Sets the LSP refresh interval.

max-lsp-tx

To set the maximum number of Link State Packets (LSPs) that can be transmitted per second in an IS-IS routing process, use the max-lsp-tx command in IS-IS router lsp-fast-flooding configuration mode. To remove the configured maximum LSP transmission rate, use the no form of this command.

max-lsp-tx lsps-per-sec

Syntax Description


`lsps-per-sec`	The maximum number of LSPs that can be transmitted per second. The default is 1000 ms. The range is from 33 through 5000 ms.

Command Default

The command is disabled by default.

Command Modes

IS-IS router lsp-fast-flooding configuration

Command History


Release	Modification
Release 24.3.1	This command was introduced.

Usage Guidelines

None

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to set maximum LSP transmission rate to 600 LSPs per second.

Router# configure terminal
Router(config)# router isis 1
Router(config-isis)# lsp-fast-flooding
Router(config-isis-lsp-fast-flooding)# max-lsp-tx 600

max-metric

To configure the Intermediate System-to-Intermediate System (IS-IS) protocol to set maximum metrics for Network Layer Reachability Information (NLRI) during router overload, use the max-metric command in IS-IS configuration mode.

max-metric [ on-startup timeout | wait-for-bgp ] [ default-route | external | interlevel | srv6-locator [ level ]

Syntax Description


on-startup	Override the default route metric value with the maximum metric value.
`timeout`	(Optional) Time in seconds to advertise the maximum metric after a reboot.
`wait-for-bgp`	(Optional) Sets the maximum metric on startup until BGP signal convergence or timeout.
default-route	Overrides the default route metric values with maximum metric value.
external	Overrides the metric of prefixes learned from another protocol with the maximum metric value.
interlevel	Overrides the metric of prefixes learned from another ISIS level with the maximum metric value.
srv6-locator	Overrides the Segment Routing IPv6 metric value with maximum metric value.
level	Sets the maximum metric value for one level only.

Command Default

Maximum metric is disabled.

Command Modes

IS-IS configuration

Command History


Release	Modification
7.0.2	This command was introduced.

Usage Guidelines

The router ignores the max-metric on-startup command and keyword combination when the IS-IS process restarts after configuring the nsf command, either with cisco or ietf keyword. This makes the IS-IS Max Metric feature compatible with the hitless switchover and process restart.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable maximum metric on a router:

Router(config)# router isis 1
Router(config-isis)# max-metric on-startup wait-for-bgp default-route external interlevel srv6-locator level 2
Router(config-isis)# exit

mesh-group (IS-IS)

To optimize link-state packet (LSP) flooding in highly meshed networks, use the mesh-group command in interface configuration mode. To remove a subinterface from a mesh group, use the no form of this command.

mesh-group {number | blocked}

no mesh-group

Syntax Description


`number`	Number identifying the mesh group of which this interface is a member. Range is 1 to 4294967295.
blocked	Specifies that no LSP flooding takes place on this interface.

Command Default

There is no mesh group configuration (normal LSP flooding).

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

LSPs first received on subinterfaces that are not part of a mesh group are flooded to all other subinterfaces in the usual way.

LSPs first received on subinterfaces that are part of a mesh group are flooded to all interfaces except those in the same mesh group. If the blocked keyword is configured on a subinterface, then a newly received LSP is not flooded out over that interface.

To minimize the possibility of incomplete flooding, you should allow unrestricted flooding over at least a minimal set of links in the mesh. Selecting the smallest set of logical links that covers all physical paths results in very low flooding, but less robustness. Ideally you should select only enough links to ensure that LSP flooding is not detrimental to scaling performance, but enough links to ensure that under most failure scenarios, no router is logically disconnected from the rest of the network. In other words, blocking flooding on all links permits the best scaling performance, but there is no flooding. Permitting flooding on all links results in very poor scaling performance.

Note

See RFC 2973 for details about the mesh group specification.

Task ID


Task ID	Operations
isis	read, write

Examples

In the following example, six interfaces are configured in three mesh groups. LSPs received are handled as follows:

LSPs first received by GigabitEthernet interface 0/1/0/0 are flooded to all interfaces except GigabitEthernet 0/1/0/1 (which is part of the same mesh group) and GigabitEthernet 0/3/0/0 (which is blocked).
LSPs first received by GigabitEthernet 0/2/0/1 are flooded to all interfaces except GigabitEthernet 0/2/0/0 (which is part of the same mesh group) and GigabitEthernet 0/3/0/0 (which is blocked).
LSPs first received by GigabitEthernet 0/3/0/0 are not ignored, but flooded as usual to all interfaces.
LSPs received first through GigabitEthernet 0/3/0/1 are flooded to all interfaces, except GigabitEthernet 0/3/0/0 (which is blocked).


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# mesh-group 10
  RP/0/RSP0/CPU0:router(config-isis-if)# exit
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# mesh-group 10
  RP/0/RSP0/CPU0:router(config-isis-if)# exit
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# mesh-group 11
  RP/0/RSP0/CPU0:router(config-isis-if)# exit
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# mesh-group 11
  RP/0/RSP0/CPU0:router(config-isis-if)# exit
  RP/0/RSP0/CPU0:routerconfig-isis)# interface GigabitEthernet 0/3/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# mesh-group 12
  RP/0/RSP0/CPU0:router(config-isis-if)# exit
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# mesh-group blocked

metric (IS-IS)

To configure the metric for an Intermediate System-to-Intermediate System (IS-IS) interface, use the metric command in address family or interface address family configuration mode. To restore the default metric value, use the no form of this command.

metric { default-metric | maximum } [ level { 1 | 2 } ]

Syntax Description

default-metric

Metric assigned to the link and used to calculate the cost from each other router using the links in the network to other destinations. Range is 1 to 63 for narrow metric and 1 to 16777214 for wide metric.

Note

Setting the default metric under address family results in setting the same metric for all interfaces that is associated with the address family. Setting a metric value under an interface overrides the default metric

maximum

Specifies maximum wide metric. All routers exclude this link from their shortest path first (SPF).

level { 1 | 2 }

(Optional) Specifies the SPF calculation for Level 1 or Level 2 independently.

Command Default

default-metric : Default is 10.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Address family configuration

Interface address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

Specifying the level keyword resets the metric only for the specified level. We highly recommend that you configure metrics on all interfaces.

Set the default metric under address family to set the same metric for all interfaces that is associated with the address family. Set a metric value under an interface to override the default metric.

We highly recommend that you configure metrics on all interfaces.

Metrics of more than 63 cannot be used with narrow metric style.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure Packet-over-SONET/SDH 0/1/0/1 interface with a default link-state metric cost of 15 for Level 1:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet /1/0/1
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-if-af)# metric 15 level 1

The following example shows how to configure a metric cost of 15 for all interfaces under address family IPv4 unicast for level 2:


RP/0/RSP0/CPU0:router# configure
RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast 
RP/0/RSP0/CPU0:router(config-isis-af)# metric 15 level 2

Related Commands


Command	Description
metric-style narrow	Configures a router running IS-IS so that it generates and accepts old-style TLV objects.
metric-style transition	Configures the software to generate and accept both old-style and new-style TLV objects.
metric-style wide	Configures the software to generate and accept only new-style TLV objects objects.

metric-style narrow

To configure the Intermediate System-to-Intermediate System (IS-IS) software to generate and accept old-style type, length, and value (TLV) objects, use the metric-style narrow command in address family configuration mode. To remove the metric-style narrow command from the configuration file and restore the system to its default condition, use the no form of this command.

metric-style narrow [transition] [level {1 | 2}]

no metric-style narrow [transition] [level {1 | 2}]

Syntax Description


transition	(Optional) Instructs the router to generate and accept both old-style and new-style TLV objects. It generates only old-style TLV objects.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

Old-style TLVs are generated.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

IS-IS traffic engineering extensions include new-style TLV objects with wider metric fields than old-style TLV objects. By default, the router generates old-style TLV objects only. To perform Multiprotocol Label Switching traffic engineering (MPLS TE), a router must generate new-style TLV objects.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the router to generate and accept only old-style TLV objects on router Level 1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# metric-style narrow level 1

Related Commands


Command	Description
metric-style transition	Configures a router to generate and accept both old-style and new-style TLV objects.
metric-style wide	Configures a router to generate and accept only new-style TLV objects.

metric-style transition

To configure the Intermediate System-to-Intermediate System (IS-IS) software to generate and accept both old-style and new-style type, length, and value (TLV) objects, use the metric-style transition command in address family configuration mode. To remove the metric-style transition command from the configuration file and restore the system to its default condition, use the no form of this command.

metric-style transition [level {1 | 2}]

no metric-style transition [level {1 | 2}]

Syntax Description


transition	Instructs the router to generate and accept both old-style and new-style TLV objects.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

Old-style TLVs are generated, if this command is not configured.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

IS-IS traffic engineering extensions include new-style TLV objects which have wider metric fields than old-style TLV objects. By default, the router generates old-style TLV objects only. To perform Multiprotocol Label Switching traffic engineering (MPLS TE), a router needs to generate new-style TLV objects.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the router to generate and accept both old-style and new-style TLV objects on Level 2:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# metric-style transition level 2

Related Commands


Command	Description
metric-style narrow	Configures a router to generate and accept only old-style TLV objects.
metric-style wide	Configures a router to generate and accept only new-style TLV objects.

metric-style wide

To configure the Intermediate System-to-Intermediate System (IS-IS) software to generate and accept only new-style type, length, and value (TLV) objects, use the metric-style wide command in address family configuration mode. To remove the metric-style wide command from the configuration file and restore the system to its default condition, use the no form of this command.

metric-style wide [transition] [level {1 | 2}]

no metric-style wide [transition] [level {1 | 2}]

Syntax Description


transition	(Optional) Instructs the router to generate and accept both old-style and new-style TLV objects. It generates only new-style TLV objects.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

Old-style TLV lengths are generated, if this command is not configured.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

IS-IS traffic engineering extensions include new-style TLV objects with wider metric fields than old-style TLV objects. If you enter the metric-style wide command, a router generates and accepts only new-style TLV objects. Therefore, the router uses less memory and fewer other resources rather than generating both old-style and new-style TLV objects.

To perform MPLS traffic engineering, a router needs to generate new-style TLV objects.

Note

This discussion of metric styles and transition strategies is oriented toward traffic engineering deployment. Other commands and models might be appropriate if the new-style TLV objects are desired for other reasons. For example, a network may require wider metrics, but might not use traffic engineering.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a router to generate and accept only new-style TLV objects on Level 1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# metric-style wide level 1

Related Commands


Command	Description
metric-style narrow	Configures a router to generate and accept only old-style TLV objects.

microloop avoidance (IS-IS)

To avoid micro-loops by delaying the convergence of all or protected prefixes, use the microloop avoidance command. Valid triggers for microloop avoidance feature are local link-down events only, such as link down, BFD down, and IS-IS adjacency down. Microloops caused by other triggers are not avoided by this feature. Consider microloop avoidance segment-routing command for extended trigger coverage.

To disable this function, use the no prefix for this command.

microloop avoidance [ protected | rib-update-delay delay ]

no microloop avoidance

Syntax Description


(none)	Delays convergence of all prefixes.
protected	(Optional) Delays convergence of protected prefixes.
rib-update-delay `delay`	(Optional) Delays convergence of all prefixes and updates RIB after the configured delay. The range is 1 to 60000 milliseconds. The default is 5000ms (for both the flavours of uloop avoidance).

Command Default

Micro-loop avoidance is disabled by default.

Command Modes

router isis configuration

Command History


Release	Modification
Release 4.3.1	This command was introduced.

Usage Guidelines

When the network converges after a link failure restoration, micro-loops can form due to inconsistencies in the forwarding tables of different routers. By delaying the convergence of prefixes, you can avoid the formation of micro-loops.

You can delay the convergence of all or protected prefixes by using the microloop avoidance command. When configured, the command applies to all prefixes by default. To enable it for only protected prefixes, use the protected option.

If another event occurs when the microloop avoidance timer is running, the microloop avoidance process is cancelled, and RIB delay timer is cancelled and prefixes are sent to RIB immediately.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure micro-loop avoidance with IS-IS:


Router# configure
Router(config)# router isis 50
Router(config-isis)# microloop avoidance rib-update-delay 400

min-lsp-arrivaltime

To control the rate of incoming LSPs (link-state packets) LSPs, use the min-lsp-arrivaltime command in router configuration mode. To remove this function use the no form of this command.

min-lsp-arrivaltime [initial-wait initial ] [secondary-wait secondary] [maximum-wait maximum] [level {1 | 2}]

no min-lsp-arrivaltime [initial-wait initial] [secondary-wait secondary] [maximum-wait maximum] [level {1 | 2}]

Syntax Description


initial-wait initial	Initial LSP calculation delay (in milliseconds). Range is 0 to 120000.
secondary-wait secondary	Hold time between the first and second LSP calculations (in milliseconds). Range is 0 to 120000.
maximum-wait maximum	Maximum interval (in milliseconds) between two consecutive LSP calculations. Range is 0 to 120000.
level { 1 \| 2 }	(Optional) Enables the LSP interval configuration for Level 1 or Level 2 independently.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration mode

Command History


Release	Modification
Release 3.9.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

This command can be used to protect a router against the possible instability of its neighbor's LSPs.

The command parameters are similair to lsp-gen-interval command and neighbors lsp-gen-interval values can be used to set the min-lsp-arrivaltime

Note

The initial-wait of minimum-lsp-arrival has no use in computing maximum counts and maximum window sizes of the LSP arrival time parameter.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure min-lsp-arrival time commands:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config)# router isis isp min-lsp-arrivaltime 
  RP/0/RSP0/CPU0:router(config)# router isis 1 min-  lsp-arrivaltime initial-wait
  RP/0/RSP0/CPU0:router(config)#router isis 1 min-lsp-arrivaltime maximum-wait 
  RP/0/RSP0/CPU0:router(config)#router isis 1 min-lsp-arrivaltime secondary-wait

mpls ldp auto-config

To enable Label Distribution Protocol (LDP) Interior Gateway Protocol (IGP) interface auto-configuration, use the mpls ldp auto-config command in IPv4 address family configuration mode. To disable LDP IGP auto-configuration, use the no form of this command.

mpls ldp auto-config

no mpls ldp auto-config

Syntax Description

This command has no keywords or arguments.

Command Default

LDP IGP auto-configuration is disabled.

Command Modes

IPv4 address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the mpls ldp auto-config command to automatically configure LDP on a set of interfaces associated with a specified IGP instance. Further, LDP IGP auto-configuration provides a means to block LDP from being enabled on a specified interface. If you do not want an IS-IS interface to have LDP enabled, use the igp auto-config disable command.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable LDP IGP auto-configuration:


  RP/0/RSP0/CPU0:router(config)# router isis isp 
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast 
  RP/0/RSP0/CPU0:router(config-isis-af)# mpls ldp auto-config

Related Commands


Command	Description
igp auto-config disable	Disables LDP IGP auto-configuration for a specific interface.

mpls ldp sync (IS-IS)

To configure Label Distribution Protocol (LDP) IS-IS synchronization, use the mpls ldp sync command in interface address family configuration mode. To disable LDP synchronization, use the no form of this command.

mpls ldp sync [level {1 | 2}]

no mpls ldp sync [level {1 | 2}]

Syntax Description


level { 1 \| 2 }	(Optional) Sets LDP synchronization for the specified level.

Command Default

If a level is not specified, LDP synchronization is set for both levels.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

MPLS VPN traffic forwarded using LDP labels can be dropped in the following instances:

A new link is introduced in the network and IS-IS has converged before LDP establishes labels.
An existing LDP session goes down while IS-IS adjacency is intact over the link.

In both instances, outbound LDP labels are not available for forwarding MPLS traffic. LDP IS-IS synchronization addresses the traffic drop. When the mpls ldp sync command is configured, IS-IS advertises the maximum possible link metric until LDP has converged over the link. The link is less preferred and least used in forwarding MPLS traffic. When LDP establishes the session and exchanges labels, IS-IS advertises the regular metric over the link.

Note

IS-IS advertises the maximum metric –1 (16777214) if wide metrics are configured since the maximum wide metric is specifically used for link exclusion from the shortest path first algorithm (SPF) (RFC 3784). However, the maximum narrow metric is unaffected by this definition.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable LDP IS-IS synchronization:


RP/0/RSP0/CPU0:router(config)# router isis isp
RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RSP0/CPU0:router(config-isis-if-af)# mpls ldp sync

Related Commands


Command	Description
show isis interface	Displays information about the IS-IS interfaces

mpls traffic-eng (IS-IS)

To configure a router running the Intermediate System-to-Intermediate System (IS-IS) protocol to flood Multiprotocol Label Switching traffic engineering (MPLS TE) link information into the indicated IS-IS level, use the mpls traffic-eng command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.

mpls traffic-eng {level-1 | level-1-2 | level-2-only}

no mpls traffic-eng [level-1 | level-1-2 | level-2-only]

Syntax Description


level-1	Specifies routing level 1.
level-1-2	Specifies routing levels 1 and 2.
level-2-only	Specifies routing level 2.

Command Default

Flooding is disabled.

Command Modes

IPv4 address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the mpls traffic-eng command, which is part of the routing protocol tree, to flood link resource information (such as available bandwidth) for appropriately configured links in the link-state packet (LSP) of the router.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to turn on MPLS traffic engineering for IS-IS level 1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# mpls  traffic-eng level-1

Related Commands


Command	Description
mpls traffic-eng router-id (IS-IS)	Specifies that the traffic engineering router identifier for the node is the IP address associated with a given interface.

mpls traffic-eng multicast-intact (IS-IS)

To enable multicast-intact for Intermediate System-to-Intermediate System (IS-IS) routes with Protocol-Independent Multicast (PIM) and Multiprotocol Label Switching (MPLS) traffic engineering, use the mpls traffic-eng multicast-intact command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.

mpls traffic-eng multicast-intact

no mpls traffic-eng [multicast-intact]

Syntax Description

This command has no keywords or arguments.

Command Default

Multicast-intact is disabled.

Command Modes

IPv4 address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

If Multiprotocol Label Switching Traffic Engineering (MPLS-TE) is configured through the IS-IS routing domain and multicast protocols (like Protocol Independent Multicast [PIM]) are also enabled, then use the mpls traffic-end multicast-intact command to install nontraffic engineering next hops in the Routing Information Base (RIB) for use by multicast. The installation of IP-only next hops is in addition to the installation of the standard set of paths for a prefix, which might be through traffic engineered tunnels.

The mpls traffic-eng multicast-intact command allows PIM to use the native hop-by-hop neighbors even though the unicast routing is using MPLS TE tunnels.

Examples

The following example shows how to enable the multicast-intact feature:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# mpls  traffic-engmulticast-intact

Related Commands


Command	Description
show isis route	Displays IP reachability information for an IS-IS instance, optionally for multicast-intact.
show isis topology	Displays a list of connected IS-IS routers in all areas, optionally for multicast-intact.

mpls traffic-eng path-selection ignore overload

To ensure that label switched paths (LSPs) are not disabled when routers have the Intermediate System-to-Intermediate System (IS-IS) overload bit set, use the mpls traffic-eng path-selection ignore overload command in global configuration mode. To disable this override, use the no form of this command.

mpls traffic-eng path-selection ignore overload

no mpls traffic-eng path-selection ignore overload

Command Default

No default behavior or values

Command Modes

Global configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

When the IS-IS overload bit avoidance feature is activated, which means that they are still available for use label switched paths (LSPs), all nodes with the overload bit set, including the following nodes, are ignored:

head nodes
mid nodes
tail nodes

Task ID


Task ID	Operations
mpls-te	read, write

Examples

The following example shows how to activate IS-IS overload bit avoidance:


  RP/0/RSP0/CPU0:router# configure
  RP/0/RSP0/CPU0:router(config)# mpls traffic-eng path-selection ignore overload

The following example shows how to deactivate IS-IS overload bit avoidance:


  RP/0/RSP0/CPU0:router# configure
  RP/0/RSP0/CPU0:router(config)# no mpls traffic-eng path-selection ignore overload

Related Commands


Command	Description
set-overload-bit	Configures a router to signal other routers not to use it as an intermediate hop in their shortest path first (SPF) calculations.

mpls traffic-eng router-id (IS-IS)

To specify the Multiprotocol Label Switching traffic engineering (MPLS TE) router identifier for the node, use the mpls traffic-eng router-id command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.

mpls traffic-eng router-id {ip-address | type interface-path-id}

no mpls traffic-eng [router-id]

Syntax Description

ip-address

IP address in four-part, dotted-decimal notation.

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

Global router identifier is used.

Command Modes

IPv4 address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The identifier of the router acts as a stable IP address for the traffic engineering configuration. This IP address is flooded to all nodes. For all traffic engineering tunnels originating at other nodes and ending at this node, you must set the tunnel destination to the traffic engineering router ID of the destination node, because that is the address used by the traffic engineering topology database at the tunnel head for its path calculation.

Note

We recommend that loopback interfaces be used for MPLS TE, because they are more stable than physical interfaces.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to specify the traffic engineering router identifier as the IP address associated with loopback interface 0:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast 
  RP/0/RSP0/CPU0:router(config-isis-af)# mpls traffic-eng router-id Loopback0

Related Commands


Command	Description
mpls traffic-eng (IS-IS)	Turns on flooding of MPLS traffic engineering link information in the indicated IGP level or area.

net

To configure an Intermediate System-to-Intermediate System (IS-IS) network entity title (NET) for the routing instance, use the net command in router configuration mode. To remove the net command from the configuration file and restore the system to its default condition, use the no form of this command.

net network-entity-title

no net network-entity-title

Syntax Description


network-entity-title	NET that specifies the area address and the system ID for an ISIS routing process.

Command Default

No NET is configured. The IS-IS instance is not operational, because a NET is mandatory.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

Under most circumstances, one and only one NET should be configured.

A NET is a network service access point (NSAP) where the last byte is always 0. On a Cisco router running IS-IS, a NET can be 8 to 20 bytes in length. The last byte is always the n-selector and must be 0. The n-selector indicates to which transport entity the packet is sent. An n-selector of 0 indicates no transport entity and means that the packet is for the routing software of the system.

The six bytes directly preceding the n-selector are the system ID. The system ID length is a fixed size and cannot be changed. The system ID must be unique throughout each area (Level 1) and throughout the backbone (Level 2).

All bytes preceding the system ID are the area ID.

A maximum of three NETs for each router is allowed. In rare circumstances, it is possible to configure two or three NETs. In such a case, the area this router is in has three area addresses. Only one area still exists, but it has more area addresses.

Configuring multiple NETs can be temporarily useful in network reconfiguration in which multiple areas are merged, or in which one area is split into more areas. Multiple area addresses enable you to renumber an area individually as needed.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a router with NET area ID 47.0004.004d.0001 and system ID 0001.0c11.1110:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# net 47.0004.004d.0001.0001.0c11.1110.00

Related Commands


Command	Description
log adjacency changes (IS-IS)	Configures the routing level for an instance of the IS-IS routing process.
router isis	Enables the IS-IS routing protocol and specifies an IS-IS instance.

nsf (IS-IS)

To enable nonstop forwarding (NSF) on the next restart, use the nsf command in router configuration mode. To restore the default setting, use the no form of this command.

nsf {cisco | ietf}

no nsf {cisco | ietf}

Syntax Description


cisco	Specifies Cisco-proprietary NSF restart.
ietf	Specifies Internet Engineering Task Force (IETF) NSF restart.

Command Default

NSF is disabled.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

NSF allows an Intermediate System-to-Intermediate System (IS-IS) instance to restart using checkpointed adjacency and link-state packet (LSP) information, and to perform restart with no impact on its neighbor routers. In other words, there is no impact on other routers in the network due to the destruction and recreation of adjacencies and the system LSP.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable Cisco proprietary NSF:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# nsf cisco

Related Commands


Command	Description
nsf interface-expires	Configures the number of resends of an an acknowledged NSF-restart acknowledgment.
nsf interface-timer	Configures the time interval after which an unacknowledged IETF NSF restart attempt is repeated.
nsf lifetime (IS-IS)	Configures the maximum route lifetime following an NSF restart.

nsf interface-expires

To configure the number of resends of an acknowledged nonstop forwarding (NSF)-restart acknowledgment, use the nsf interface-expires command in router configuration mode. To restore the default value, use the no form of this command.

nsf interface-expires number

no nsf interface-expires

Syntax Description


number	Number of resends. Range is 1 to 3.

Command Default

number : 3 resends

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

When a hello packet sent with the NSF restart flag set is not acknowledged, it is re-sent. Use the nsf interface-expires command to control the number of times the NSF hello is re-sent. When this limit is reached on an interface, any neighbor previously known on that interface is assumed to be down and the initial shortest path first (SPF) calculation is permitted, provided that all other necessary conditions are met.

The total time period available for adjacency reestablishment (interface-timer * interface-expires) should be greater than the expected total NSF restart time.

The nsf interface-expires command applies only to Internet Engineering Task Force (IETF)-style NSF. It has no effect if Cisco-proprietary NSF is configured.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to allow only one retry attempt on each interface if an IETF NSF restart signal is not acknowledged:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# nsf ietf
  RP/0/RSP0/CPU0:router(config-isis)# nsf interface-expires 1

Related Commands


Command	Description
hello-multiplier	Specifies the number of IS-IS hello packets a neighbor must miss before the router should declare the adjacency as down.
nsf interface-timer	Configures the time interval after which an unacknowledged IETF NSF restart attempt is repeated.

nsf interface-timer

To configure the time interval after which an unacknowledged Internet Engineering Task Force (IETF) nonstop forwarding (NSF) restart attempt is repeated, use the nsf interface-timer command in router configuration mode. To restore the default value, use the no form of this command.

nsf interface-timer seconds

no nsf interface-timer

Syntax Description


seconds	NSF restart time interval (in seconds). Range is 3 to 20 seconds.

Command Default

seconds : 10 seconds

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

When the IETF NSF restart process begins, hello packets send an NSF restart flag that must be acknowledged by the neighbors of the router. Use the nsf interface-timer command to control the restart time interval after the hello packet is re-sent. The restart time interval need not match the hello interval.

The nsf interface-timer command applies only to IETF-style NSF. It has no effect if Cisco proprietary NSF is configured.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to ensure that a hello packet with the NSF restart flag set is sent again every 5 seconds until the flag is acknowledged:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# nsf ietf
  RP/0/RSP0/CPU0:router(config-isis)# nsf interface-timer 5

Related Commands


Command	Description
nsf interface-expires	Configures the number of resends of an acknowledged NSF-restart acknowledgment.
hello-interval (IS-IS)	Specifies the length of time between hello packets that the software sends.

nsf lifetime (IS-IS)

To configure the maximum route lifetime following a nonstop forwarding (NSF) restart, use the nsf lifetime command in router configuration mode. To restore the default value, use the no form of this command.

nsf lifetime seconds

no nsf lifetime

Syntax Description


seconds	Maximum route lifetime (in seconds) following an NSF restart. Range is 5 to 300 seconds.

Command Default

seconds : 60 seconds (1 minute)

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the nsf lifetime command to set the maximum available time for the reacquisition of checkpointed adjacencies and link-state packets (LSPs) during a Cisco proprietary NSF restart. LSPs and adjacencies not recovered during this time period are abandoned, thus causing changes to the network topology.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the router to allow only 20 seconds for the entire NSF process:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# nsf cisco
  RP/0/RSP0/CPU0:router(config-isis)# nsf lifetime 20

passive (IS-IS)

To suppress Intermediate System-to-Intermediate System (IS-IS) packets from being transmitted to the interface and received packets from being processed on the interface, use the passive command in interface configuration mode. To restore IS-IS packets coming to an interface, use the no form of this command.

passive

no passive

Command Default

Interface is active.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the router to suppress IS-IS packets on GigabitEthernet interface 0/1/0/1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# passive

Related Commands


Command	Description
suppressed	Allows the IS-IS interface to participate in forming adjacencies without advertising connected prefixes in the LSPs.

point-to-point

To configure a network of only two networking devices that use broadcast media and the integrated Intermediate System-to-Intermediate System (IS-IS) routing protocol to function as a point-to-point link instead of a broadcast link, use the point-to-point command in interface configuration mode. To disable the point-to-point usage, use the no form of this command.

point-to-point

no point-to-point

Syntax Description

This command has no keywords or arguments.

Command Default

Interface is treated as broadcast if connected to broadcast media.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the point-to-point command only on broadcast media in a network with two networking devices. The command causes the system to issue packets point-to-point rather than as broadcasts. Configure the command on both networking devices in the network.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure a 10-Gb Ethernet interface to act as a point-to-point interface:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface TenGigE 0/6/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# point-to-point

priority (IS-IS)

To configure the priority of designated routers, use the priority command in interface configuration mode. To reset the default priority, use the no form of this command.

priority value [level {1 | 2}]

no priority [value] [level {1 | 2}]

Syntax Description


`value`	Priority of a router. Range is 0 to 127.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

value : 64

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Priorities can be configured for Level 1 and Level 2 independently. Specifying Level 1 or Level 2 resets priority only for Level 1 or Level 2 routing, respectively. Specifying no level allows you to configure all levels.

The priority is used to determine which router on a LAN is the designated router or Designated Intermediate System (DIS). The priorities are advertised in the hello packets. The router with the highest priority becomes the DIS.

In the Intermediate System-to-Intermediate System (IS-IS) protocol, there is no backup designated router. Setting the priority to 0 lowers the chance of this system becoming the DIS, but does not prevent it. If a router with a higher priority comes online, it takes over the role from the current DIS. For equal priorities, the higher MAC address breaks the tie.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to give Level 1 routing priority by setting the priority level to 80. This router is now more likely to become the DIS.


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface TenGigE0/6/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# priority 80 level 1

propagate level

To propagate routes from one Intermediate System-to-Intermediate System (IS-IS) level into another level, use the propagate level command in address family configuration mode. To disable propagation, use the no form of this command.

propagate level {1 | 2} into level {1 | 2} route-policy route-policy-name

no propagate level {1 | 2} into level {1 | 2}

Syntax Description


level { 1 \| 2 }	Propagates from routing Level 1 or Level 2 routes.
into	Propagates from Level 1 or Level 2 routes into Level 1 or Level 2 routes.
route-policy `route-policy-name`	Specifies a configured route policy.

Command Default

Route leaking (Level 2 to Level 1) is disabled.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

In general, route propagation from Level 1 to Level 2 is automatic. You might want to use this command to better control which Level 1 routes can be propagated into Level 2.

Propagating Level 2 routes into Level 1 is called route leaking. Route leaking is disabled by default. That is, Level 2 routes are not automatically included in Level 1 link-state packets (LSPs). If you want to leak Level 2 routes into Level 1, you must enable that behavior by using this command.

Propagation from Level 1 into Level 1 and from Level 2 into Level 2 is not allowed.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to redistribute Level 2 routes to Level 1:


  RP/0/RSP0/CPU0:router(config)# ipv4 access-list 101 permit ip 10.0.0.0 255.0.0.0 10.1.0.1 0.255.255.255
  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# net 49.1234.2222.2222.2222.00
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# propagate level 2 into level 1 route-policy policy_a

Related Commands


Command	Description
redistribute (IS-IS)	Redistributes routes from one routing domain into a specified IS-IS instance.

protocol shutdown (IS-IS)

To disable an instance of the Intermediate System-to-Intermediate System (IS-IS) protocol, so that it cannot form an adjacency on any interface, use the protocol shutdown command in the isis configuration mode. To re-enable the IS-IS protocol, use the no form of this command.

protocol shutdown

no protocol shutdown

Command Default

None

Command Modes

isis configuration

Command History


Release	Modification
Release 24.4.1	This command was introduced.

Usage Guidelines

Use the protocol shutdown command to disable the IS-IS protocol for a specific routing instance without removing any existing IS-IS configuration parameters.

This command is similar to executing the following sample configuration:


router isis 1
 set-overload-bit
 exit
router isis 1
 interface HundredGigE 0/1/0/3
  shutdown

Task ID


Task ID	Operations
isis	read, write

Examples

This example shows how to disable the IS-IS.

Router# config
Router(config)# router isis 1
Router(config-isis)# protocol shutdown

psnp-interval

To configure the interval at which the Intermediate System to Intermediate System (IS-IS) protocol sends Partial Sequence Number PDUs (PSNPs) to acknowledge received Link State PDUs (LSPs), use the psnp-interval in router configuration mode.

psnp-interval milliseconds

Syntax Description


`milliseconds`	The interval, specified in milliseconds, at which PSNPs are sent to acknowledge received LSPs. The range is from 1 to 5000 milliseconds. The default value is 50 milliseconds.

Command Default

This command is disabled by default.

Command Modes

Router configuration

Command History


Release	Modification
Release 24.3.1	This command was introduced.

Usage Guidelines

None

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to configure the PSNP interval to 100 milliseconds for an IS-IS process tagged 1:

Router(config)# router isis 1
Router(config-isis)# psnp-interval 100

redistribute (IS-IS)

To redistribute routes from one routing protocol into Intermediate System-to-Intermediate System (IS-IS), use the redistribute command in address family configuration mode. To remove the redistribute command from the configuration file and restore the system to its default condition in which the software does not redistribute routes, use the no form of this command.

Border Gateway Protocol (BGP)

redistribute bgp process-id [level-1 | level-2 | level-1-2] [metric metric-value] [metric-type {internal | external}] [route-policy route-policy-name]

no redistribute

Connected Routes

redistribute connected [level-1 | level-2 | level-1-2] [metric metric-value] [metric-type {internal | external}] [route-policy route-policy-name]

no redistribute

Intermediate System-to-Intermediate System (IS-IS)

redistribute isis process-id [level-1 | level-2 | level-1-2] [metric metric-value] [metric-type {internal | external}] [route-policy route-policy-name] [ down-flag-clear ]

no redistribute

Open Shortest Path First (OSPF)

redistribute ospf process-id [level-1 | level-2 | level-1-2] [match {external [1 | 2] | internal | nssa-external [1 | 2]}] [metric metric-value] [metric-type {internal | external}] [route-policy route-policy-name]

no redistribute

Open Shortest Path First Version 3 (OSPFv3)

redistribute ospfv3 process-id [level-1 | level-2 | level-1-2] [match {external [1 | 2] | internal | nssa-external [1 | 2]}] [metric metric-value] [metric-type {internal | external}] [route-policy route-policy-name]

no redistribute

Static Routes

redistribute static [level-1 | level-2 | level-1-2] [metric metric-value] [metric-type {1 | 2 }] [route-policy route-policy-name]

no redistribute

Syntax Description


`process-id`	For the bgp keyword, an autonomous system number has the following ranges: Range for 2-byte Autonomous system numbers (ASNs) is 1 to 65535. Range for 4-byte Autonomous system numbers (ASNs) in asplain format is 1 to 4294967295. Range for 4-byte Autonomous system numbers (ASNs) is asdot format is 1.0 to 65535.65535. For the isis keyword, an IS-IS instance identifier from which routes are to be redistributed. For the ospf keyword, an OSPF process name from which routes are to be redistributed. The value takes the form of a string. A decimal number can be entered, but it is stored internally as a string. For the ospfv3 keyword, an OSPFv3 process name from which routes are to be redistributed. The value takes the form of a string. A decimal number can be entered, but it is stored internally as a string.
level-1	(Optional) Specifies that redistributed routes are advertised in the Level-1 LSP of the router.
level-1-2	(Optional) Specifies that redistributed routes are advertised in the Level-1-2 LSP of the router.
level-2	(Optional) Specifies that redistributed routes are advertised in the Level-2 LSP of the router.
metric `metric-value`	(Optional) Specifies the metric used for the redistributed route. Range is 0 to 16777215. The `metric-value` must be consistent with the IS-IS metric style of the area and topology into which the routes are being redistributed.
metric-type { internal \| external }	(Optional) Specifies the external link type associated with the route advertised into the ISIS routing domain. It can be one of two values: external internal –Use the internal keyword to set IS-IS internal metric-type external –Use the external keyword to set IS-IS external metric-type Any route with an internal metric (however large the metric is) is preferred over a route with external metric (however small the metric is).
route-policy `route-policy-name`	(Optional) Specifies the identifier of a configured policy. A policy is used to filter the importation of routes from this source routing protocol to IS-IS.
match { internal \| external [ 1 \| 2 ] \| nsaa-external [ 1 \| 2 ]}	(Optional) Specifies the criteria by which OSPF routes are redistributed into other routing domains. It can be one or more of the following: internal —Routes that are internal to a specific autonomous system (intra- and interarea OSPF routes). external [ 1 \| 2 ]—Routes that are external to the autonomous system, but are imported into OSPF as Type 1 or Type 2 external routes. nssa-external [ 1 \| 2 ]—Routes that are external to the autonomous system, but are imported into OSPF as Type 1 or Type 2 not-so-stubby area (NSSA) external routes. For the external and nssa-external options, if a type is not specified, then both Type 1 and Type 2 are assumed.
down-flag-clear	(Optional) Specifies that routes redistributed from another IS-IS instance should be advertised with the up/down bit set to zero. This is contrary to the behavior specified by RFC 5305 and RFC 7775 and can lead to route loops.

Command Default

Level 2 is configured if no level is specified.

metric-type: internal

match : If no match keyword is specified, all OSPF routes are redistributed.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Asplain format for 4-byte Autonomous system numbers notation was supported.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Note

When redistributing routes (into IS-IS) using both command keywords for setting or matching of attributes and a route policy, the routes are run through the route policy first, followed by the keyword matching and setting.

Use the redistribute command to control the redistribution of routes between separate IS-IS instances. To control the propagation of routes between the levels of a single IS-IS instance, use the propagate level command.

Only IPv4 OSPF addresses can be redistributed into IS-IS IPv4 address families.

Task ID


Task ID	Operations
isis	read, write

Examples

In this example, IS-IS instance isp_A readvertises all of the routes of IS-IS instance isp_B in Level 2 LSP. Note that the level-2 keyword affects which levels instance isp_A advertises the routes in and has no impact on which routes from instance isp_B are advertised. (Any Level 1 routes from IS-IS instance isp_B are included in the redistribution.


  RP/0/RSP0/CPU0:router(config)# router isis isp_A
  RP/0/RSP0/CPU0:router(config-isis)# net 49.1234.2222.2222.2222.00
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# redistribute isis isp_B level-2
  !
  RP/0/RSP0/CPU0:router(config)# router isis isp_B
  RP/0/RSP0/CPU0:router(config-isis)# is-type level 1
  RP/0/RSP0/CPU0:router(config-isis)# net 49.4567.2222.2222.2222.00
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast

Related Commands


Command	Description
propagate level	Propagates routes from one IS-IS level into another level.

remote-psnp-delay

To specify the maximum delay, in milliseconds, that the router should wait for a Partial Sequence Number Protocol (PSNP) acknowledgment from neighbors after sending a Link State Packet (LSP), use the remote-psnp-delay command in appropriate mode. To remove the configured maximum delay, use the no form of this command.

remote-psnp-delay milliseconds

Syntax Description


`milliseconds`	Maximum delay, in milliseconds, that the router should wait for a PSNP acknowledgment from neighbors after sending a LSP. The range is from 1 through 5000 ms.

Command Default

The command is disabled by default.

Command Modes

IS-IS router lsp-fast-flooding configuration

Interface configuration

Command History


Release	Modification
Release 24.3.1	This command was introduced.

Usage Guidelines

The order of precedence of the configuration using the remote-psnp-delay command is as follows:

The remote-psnp-delay command in interface configuration mode.
The value in the PSNP sub-TLV received from the neighbour, if any.
The remote-psnp-delay command in router configuration mode.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to set the PSNP acknowledgment delay to 600 milliseconds on a device.

Router# configure terminal
Router(config)# router isis 1
Router(config-isis)# lsp-fast-flooding
Router(config-isis-lsp-fast-flooding)# remote-psnp-delay 600
Router(config-isis-lsp-fast-flooding)# commit

This example shows how to set the PSNP acknowledgment delay to 600 milliseconds on an interface.

Router# configure terminal
Router(config)# router isis 1
Router(config-isis)# interface GigabitEthernet0/0/0/0
Router(config-isis-if)# remote-psnp-delay 600

retransmit-interval (IS-IS)

To configure the amount of time between retransmission of each Intermediate System-to-Intermediate System (IS-IS) link-state packet (LSP) on a point-to-point link, use the retransmit-interval command in interface configuration mode. To restore the default value, use the no form of this command.

retransmit-interval seconds [level {1 | 2}]

no retransmit-interval [seconds [level {1 | 2}]]

Syntax Description


`seconds`	Time (in seconds) between consecutive retransmissions of each LSP. It is an integer that should be greater than the expected round-trip delay between any two networking devices on the attached network. Range is 0 to 65535 seconds.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

seconds : 5 seconds

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The retransmit-interval command has no effect on LAN (multipoint) interfaces. On point-to-point links, the value can be increased to enhance network stability.

Because retransmissions occur only when LSPs are dropped, setting this command to a higher value has little effect on reconvergence. The more neighbors networking devices have, and the more paths over which LSPs can be flooded, the higher this value can be made.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure GigabitEthernet interface 0/2/0/1 for retransmission of IS-IS LSPs every 60 seconds for a large serial line:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# retransmit-interval 60

Related Commands


Command	Description
retransmit-throttle-interval	Configures the amount of time between retransmissions of any IS-IS LSPs on a point-to-point interface.

retransmit-throttle-interval

To configure minimum interval between retransmissions of different Intermediate System-to-Intermediate System (IS-IS) link-state packets (LSPs) on a point-to-point interface, use the retransmit-throttle-interval command in interface configuration mode. To remove the command from the configuration file and restore the system to its default condition, use the no form of this command.

retransmit-throttle-interval milliseconds [level {1 | 2}]

no retransmit-throttle-interval [milliseconds [level {1 | 2}]]

Syntax Description


`milliseconds`	Minimum delay (in milliseconds) between LSP retransmissions on the interface. Range is 0 to 65535.
level { 1 \| 2 }	(Optional) Specifies routing Level 1 or Level 2 independently.

Command Default

Default is 0.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the retransmit-throttle-interval command to define the minimum period of time that must elapse between retransmitting any two consecutive LSPs on an interface. The retransmit-throttle-interval command may be useful in very large networks with many LSPs and many interfaces as a way of controlling LSP retransmission traffic. This command controls the rate at which LSPs can be re-sent on the interface.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure GigabitEthernet interface 0/2/0/1 to limit the rate of LSP retransmissions to one every 300 milliseconds:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# retransmit-throttle-interval 300

Related Commands


Command	Description
lsp-gen-interval	Configures the minimum interval time between regenerating the same LSP.
retransmit-interval (IS-IS)	Configures the amount of time between retransmission of each IS-IS LSP over a point-to-point link.

router isis

To enable the Intermediate System-to-Intermediate System (IS-IS) routing protocol and to specify an IS-IS instance, use the router isis command in global configuration mode. To disable IS-IS routing, use the no form of this command.

router isis instance-id

no router isis instance-id

Syntax Description


instance-id	Name of the routing process. Maximum number of characters is 40.

Command Default

An IS-IS routing protocol is not enabled.

Command Modes

Global configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

Use the router isis command to create an IS-IS routing process. An appropriate network entity title (NET) must be configured to specify the address of the area (Level 1) and system ID of the router. Routing must be enabled on one or more interfaces before adjacencies may be established and dynamic routing is possible.

Multiple IS-IS processes can be configured. Up to eight processes are configurable. A maximum of five IS-IS instances on a system are supported.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure IS-IS for IP routing:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# net 49.0001.0000.0001.00

Related Commands


Command	Description
net	Configures an IS-IS NET for the routing process.

route source first-hop

To replace the originating route with first-hop for multicast traffic, use the route source first-hop command in ISIS address-family submode. To remove the first-hop for multicast traffic, use the no form of this command.

route source first-hop

This command has no keywords or arguments.

Command Default

no route source first-hop is enabled.

Command Modes

ISIS address-family submode

Command History


Release	Modification
Release 6.0	This command was introduced.

Usage Guidelines

This command replaces the originating router address with first-hop router address in the RIB table and facilitates computing alternate paths for multicast traffic. This feature is incompatible with other IOS-XR features, such as MPLS-TE inter-area tunnels. You must use the route source first-hop command only to support MoFRR with multicast multipath.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to replace the originating route with first-hop:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 multicast
  RP/0/RSP0/CPU0:router(config-isis-af)# route source first-hop

Related Commands


Command	Description
net	Configures an IS-IS NET for the routing process.

set default-isis-instance

When multiple IS-IS instances are configured on a router, by default, show isis commands display information from all IS-IS instances. To display information from only one specific IS-IS instance, use the set default-isis-instance instance-name command in the EXEC mode.

When the default IS-IS instance is set, all the show IS-IS commands during the terminal session display only information from that default IS-IS instance. To revert back to the default behaviour of displaying information from all IS-IS instances, use the set default-isis-instance all command.

set default-isis-instance { instance-name | all }

Syntax Description


`instance-name`	Displays information for the specified `instance-name` when running show isis commands.
all	Displays information from all configured IS-IS instances when running show isis commands.

Command Default

By default, all configured IS-IS instances are displayed when you run any show isis command.

Command Modes

EXEC mode

Command History


Release	Modification
Release 24.2.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

Example 1: This example shows how to set a specific IS-IS instance as the default instance.

RP/0/1/CPU0:ios#set default-isis-instance india
Tue Apr 23 11:47:04.353 CEST
%% Default isis instance is set to  india

Example 2: This example uses the show isis summary command to display information from the default instance set in Example 1.


RP/0/1/CPU0:ios#show isis summary 
Tue Apr 23 11:47:10.802 CEST

                               (L1/L2)    (L1/L2)      (L1/L2)      (IPv4/IPv6) 
Tag                    Level   Adj        Routers      LSPs         Routes      
---                    -----   ---        -------      ----         ------      
india                  L2      0/1        0/2          0/2          0/0         
RP/0/1/CPU0:ios#

Example 3: This example shows how to set all configured IS-IS instances as default instances.

RP/0/1/CPU0:ios#set default-isis-instance all
Tue Apr 23 11:47:19.308 CEST
%% Default isis instance is set to  all

Example 4: This example uses the show isis summary command to display information from all the configured instances set in Example 3.


RP/0/1/CPU0:ios#show isis summary 
Tue Apr 23 11:47:24.697 CEST

                               (L1/L2)    (L1/L2)      (L1/L2)      (IPv4/IPv6) 
Tag                    Level   Adj        Routers      LSPs         Routes      
---                    -----   ---        -------      ----         ------      
eu                     L2      0/2        0/6          0/6          5/5         
india                  L2      0/1        0/2          0/2          0/0         
RP/0/1/CPU0:ios#

set-overload-bit

To configure the router to signal other routers not to use it as an intermediate hop in their shortest path first (SPF) calculations, use the set-overload-bit command in router configuration mode. To remove the designation, use the no form of this command.

set-overload-bit [on-startup {delay | wait-for-bgp}] [level {1 | 2}] [advertise {external | interlevel}]

no set-overload-bit [on-startup {delay | wait-for-bgp}] [level {1 | 2}]

Syntax Description


on-startup	(Optional) Sets the overload bit only temporarily after reboot.
`delay`	(Optional) Time (in seconds) to advertise when the router is overloaded after reboot. Range is 5 to 86400 seconds (86400 seconds = 1 day).
wait-for-bgp	(Optional) Sets the overload bit on startup until the Border Gateway Protocol (BGP) signals converge or time out.
level { 1 \| 2 }	(Optional) Specifies the overload bit for Level 1 or Level 2 independently.

Command Default

The overload bit is not set.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Router configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the set-overload-bit command to force the router to set the overload bit in its nonpseudonode link-state packets (LSPs). Normally the setting of the overload bit is allowed only when a router experiences problems. For example, when a router is experiencing a memory shortage, the reason might be that the link-state database is not complete, resulting in an incomplete or inaccurate routing table. If the overload bit is set in the LSPs of the unreliable router, other routers can ignore the router in their SPF calculations until it has recovered from its problems. The result is that no paths through the unreliable router are seen by other routers in the Intermediate System-to-Intermediate System (IS-IS) area. However, IP prefixes directly connected to this router are still reachable.

The set-overload-bit command can be useful when you want to connect a router to an IS-IS network, but do not want real traffic flowing through it under any circumstances.

Routers with overload bit set are:

A test router in the lab, connected to a production network.
A router configured as an LSP flooding server, for example, on a nonbroadcast multiaccess (NBMA) network, in combination with the mesh group feature.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to configure the overload bit:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# set-overload-bit

set-attached-bit

To configure an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit in the Level 1 link-state packet (LSP), use the set-attached-bit command in address family configuration mode. To remove the set-attached-bit command from the configuration file and restore the system to its default condition, use the no form of this command.

set-attached-bit

no set-attached-bit

Command Default

Attached bit is not set in the LSP.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the set-attached bit command to set an IS-IS instance with an attached bit in the Level 1 LSP that allows another IS-IS instance to redistribute Level 2 topology. The attached bit is used when the Level 2 connectivity from another IS-IS instance is advertised by the Level 1 attached bit.

Cisco IOS XR software does not support multiple Level 1 areas in a single IS-IS routing instance. But the equivalent functionality is achieved by redistribution of routes between two IS-IS instances by using the redistribute (IS-IS) command.

The attached bit is configured for a specific address family only if the single-topology command is not configured.

Note

If connectivity for the Level 2 instance is lost, the attached bit in the Level 1 instance LSP continues sending traffic to the Level 2 instance and causes the traffic to be dropped.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to set the attached bit for a Level 1 instance that allows the Level 2 instance to redistribute routes from the Level 1 instance:


  RP/0/RSP0/CPU0:router(config)# router isis 1
  RP/0/RSP0/CPU0:router(config-isis)# net 49.0001.0001.0001.0001.00
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# redistribute isis 2 level 2
  !
  RP/0/RSP0/CPU0:router(config-isis-af)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-isis-af-if)# address-family ipv4 unicast
  !
  !
  RP/0/RSP0/CPU0:router(config)# router isis 2
  RP/0/RSP0/CPU0:router(config-isis)# is-type level-1
  RP/0/RSP0/CPU0:router(config-isis)# net 49.0002.0001.0001.0002.00
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# set-attached-bit
  !
  RP/0/RSP0/CPU0:routerfig-isis-af)# interface GigabitEthernet 0/1/0/0
  RP/0/RSP0/CPU0:router(config-isis-af-if)# address-family ipv4 unicast

Related Commands


Command	Description
redistribute (IS-IS)	Redistributes routes from one IS-IS instance into another instance.
single-topology	Configures the link topology for IPv4 when IPv6 is configured.

show isis

The show isis command displays general information about an IS-IS instance and protocol operation. If the instance ID is not specified, the command shows information about all IS-IS instances.

show isis [instance instance-id]

Syntax Description

instance instance-id

(Optional) Displays the IS-IS adjacencies for the specified IS-IS instance only.

Note

The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays IS-IS adjacencies for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

For each instance, the first line of output lists the IS-IS instance ID with the following lines identifying the IS-IS system ID, supported levels (level 1, level 2, or level-1-2), configured area addresses, active area addresses, status (enabled or not) and type (Cisco or IETF) of nonstop forwarding (NSF), and the mode in which the last IS-IS process startup occurred.

Next, the status of each configured address family (or just IPv4 unicast if none are configured) is summarized. For each level (level 1 or level 2), the metric style (narrow or wide) generated and accepted is listed along with the status of incremental shortest path first (iSPF) computation (enabled or not). Then redistributed protocols are listed, followed by the administrative distance applied to the redistributed routes.

Finally, the running state (active, passive, or disabled) and configuration state (active or disabled) of each IS-IS interface is listed.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis command:


  Router# show isis
  Wed Aug 20 23:54:55.043 PST DST
  
  IS-IS Router: lab
    System Id: 0000.0000.0002 
    IS Levels: level-2-only
    Manual area address(es):
      49.1122
    Routing for area address(es):
      49.1122
    Non-stop forwarding: Disabled
    Most recent startup mode: Cold Restart
    Topologies supported by IS-IS:
      IPv4 Unicast
        Level-2
          Metric style (generate/accept): Narrow/Narrow
          Metric: 10
          ISPF status: Disabled
        No protocols redistributed
        Distance: 115
    Interfaces supported by IS-IS:
      Loopback0 is running passively (passive in configuration)
      POS0/1/0/2 is running actively (active in configuration)
      POS0/1/0/3 is running actively (active in configuration

This table describes the significant fields shown in the display.

Table 3. show isis Field Descriptions
Field	Description
IS-IS Router	IS-IS instance ID.
System Id	IS-IS system ID.
IS Levels	Supported levels for the instance.
Manual area address(es)	Domain and area.
Routing for area address(es):	Configured area addresses and active area addresses.
Non-stop forwarding	Status (enabled or not) and type (Cisco or IETF) of nonstop forwarding (NSF).
Most recent startup mode	The mode in which the last IS-IS process startup occurred.
Topologies supported by IS-IS	The summary of the status of each configured address family (or just IPv4 unicast if none are configured).
Redistributed protocols	List of redistributed protocols, followed by the administrative distance applied to the redistributed routes.
Metric style (generate/accept)	The status of each configured address family (or just IPv4 unicast if none are configured) is summarized. For each level (level 1 or level 2), the metric style (narrow or wide) generated and accepted is listed along with the status of incremental shortest path first (iSPF) computation (enabled or not).
Interfaces supported by IS-IS	The running state (active, passive, or disabled) and configuration state (active or disabled) of each IS-IS interface.

show isis adjacency

To display Intermediate System-to-Intermediate System (IS-IS) adjacencies, use the show isis adjacency command in EXEC mode.

show isis [instance instance-id] adjacency [level {1 | 2}] [type interface-path-id] [detail] [systemid system-id]

Syntax Description

instance instance-id

(Optional) Displays the IS-IS adjacencies for the specified IS-IS instance only.

The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.

level { 1 | 2 }

(Optional) Displays the IS-IS adjacencies for Level 1 or Level 2 independently.

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

detail

(Optional) Displays neighbor IP addresses and active topologies.

systemid system-id

(Optional) Displays the information for the specified router only.

Command Default

No instance ID specified displays IS-IS adjacencies for all the IS-IS instances.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis adjacency command:


  RP/0/RSP0/CPU0:router# show isis adjacency
  
  IS-IS p Level-1 adjacencies:
  System Id      Interface        SNPA           State Hold     Changed  NSF      BFD
  12a4           PO0/1/0/1        *PtoP*         Up    23       00:00:06 Capable  Init
  12a4           Gi0/6/0/2        0004.2893.f2f6 Up    56       00:04:01 Capable  Up
  
  Total adjacency count: 2
  
  IS-IS p Level-2 adjacencies:
  System Id      Interface        SNPA           State Hold     Changed  NSF      BFD
  12a4           PO0/1/0/1        *PtoP*         Up    23       00:00:06 Capable  None
  12a4           Gi0/6/0/2        0004.2893.f2f6 Up    26       00:00:13 Capable  Init
  
  Total adjacency count: 2

This table describes the significant fields shown in the display.

Table 4. show isis adjacency Field Descriptions
Field	Description
Level-1	Level 1 adjacencies.
Level-2	Level 2 adjacencies.
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or the hostname dynamic disable command has been executed, the 6-octet system ID is used.
Interface	Interface used to reach the neighbor.
SNPA	Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
State	Adjacency state of the neighboring interface. Valid states are Down, Init, and Up.
Holdtime	Hold time of the neighbor.
Changed	Time the neighbor has been up (in hours:minutes:seconds).
NSF	Specifies whether the neighbor can adhere to the IETF-NSF restart mechanism.
BFD	Specifies the Bidirectional Forwarding Detection (BFD) status for the interface. Valid status are None—BFD is not configured. Init—BFD session is not up. One reason is that other side is not yet enabled. Up—BFD session has been established. Down—BFD session holdtime expired.

Related Commands


Command	Description
show isis neighbors	Displays information about IS-IS neighbors.

show isis adjacency-log

To display the Intermediate System-to-Intermediate System (IS-IS) adjacency log, use the show isis adjacency-log command in EXEC mode.

show isis adjacency-log [level {1 | 2}] [last number | first number]

Syntax Description


level { 1 \| 2 }	(Optional) Displays the IS-IS adjacency log for Level 1 or Level 2 independently.
last `number`	(Optional) Specifies that the output is restricted to the last `number` of entries. Range is 1 to 100.
first `number`	(Optional) Specifies that the output is restricted to the first `number` of entries. Range is 1 to 100.

Command Default

No default behavior or values

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis adjacency-log command:


  RP/0/RSP0/CPU0:router# show isis adjacency-log
  
     IS-IS 10 Level 1 Adjacency log
  When           System          Interface          State   Details
  4d00h          12a1            PO0/5/0/0          d -> i
  4d00h          12a1            PO0/5/0/0          i -> u  New adjacency
                                                            IPv4 Unicast Up
  4d00h          12a1            Gi0/6/0/0          d -> u  New adjacency
  4d00h          12a1            Gi0/6/0/0          u -> d  Interface state
  down
  3d17h          12a1            Gi0/6/0/0          d -> u  New adjacency
  3d17h          12a1            Gi0/6/0/0          u -> d  Interface state
  down
  01:44:07       12a1            Gi0/6/0/0          d -> u  New adjacency
  
     IS-IS 10 Level 2 Adjacency log
  When           System          Interface          State   Details
  4d00h          12a1            PO0/5/0/0          d -> i
  4d00h          12a1            PO0/5/0/0          i -> u  New adjacency
                                                            IPv4 Unicast Up
  4d00h          12a1            Gi0/6/0/0          d -> u  New adjacency
  4d00h          12a1            Gi0/6/0/0          u -> d  Interface state
  down
  3d17h          12a1            Gi0/6/0/0          d -> u  New adjacency
  3d17h          12a1            Gi0/6/0/0          u -> d  Interface state
  down
  01:44:07       12a1            Gi0/6/0/0          d -> u  New adjacency

This table describes the significant fields shown in the display.

Table 5. show isis adjacency-log Field Descriptions
Field	Description
When	Elapsed time (in hh:mm:ss) since the event was logged.
System	System ID of the adjacent router.
Interface	Specific interface involved in the adjacency change.
State	State transition for the logged event.
Details	Description of the adjacency change.

show isis checkpoint adjacency

To display the Intermediate System-to-Intermediate System (IS-IS) checkpoint adjacency database, use the show isis checkpoint adjacency command in EXEC mode.

show isis [instance instance-id] checkpoint adjacency

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS checkpoint adjacencies for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays IS-IS checkpoint adjacencies for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the show isis checkpoint adjacency command to display the checkpointed adjacencies. With this information you can restore the adjacency database during a Cisco proprietary nonstop forwarding (NSF) restart. This command, with the show isis adjacency command, can be used to verify the consistency of the two databases.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis checkpoint adjacency command:


 RP/0/RSP0/CPU0:router# show 
            isis 
            checkpoint 
            adjacency 
  
  Interface        Level  System ID        State  Circuit ID          Chkpt ID
  Gi3/0/0/1           1    router-gsr8      Up     0001.0000.0008.04   80011fec
  Gi0/4/0/1           1    router-gsr9      Up     0001.0000.0006.01   80011fd8
  Gi/0/0/1           2    router-gsr8      Up     0001.0000.0008.04   80011fc4

This table describes the significant fields shown in the display.

Table 6. show isis checkpoint adjacency Field Descriptions
Field	Description
Interface	Interface used to reach the neighbor.
Level	Lists either routers with Level 1 or Level 2 adjacency configured.
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
State	State of the neighboring interface.
Circuit ID	Unique ID issued to a circuit at its creation.
Chkpt ID	Unique ID issued to the checkpoint at its creation.

Related Commands


Command	Description
show isis adjacency	Displays IS-IS adjacencies.
show isis checkpoint lsp	Displays the IS-IS checkpoint LSP database.

show isis checkpoint interface

To display the Intermediate System-to-Intermediate System (IS-IS) checkpoint interfaces, use the show isis checkpoint interface command in EXEC mode.

show isis checkpoint interface

This command has no keywords or arguments.

Command Default

No default behavior or values

Command Modes

EXEXEC EC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis checkpoint interface command:


  RP/0/RSP0/CPU0:router# show isis checkpoint interface 
       
  IS-IS 10 checkpoint interface
  Interface         Index  CircNum  DIS Areas    Chkpt ID
  PO0/5/0/0         0      0        NONE         80002fe8
  Gi0/6/0/0         1      3        L1L2         80002fd0

This table describes the significant fields shown in the display.

Table 7. show isis checkpoint interface Field Descriptions
Field	Description
Interface	Interface used to reach the neighbor.
Index	Interface index assigned to an interface upon its creation.
CircNum	Unique ID issued to a circuit internally.
DIS Areas	Designated Intermediate System area.
Chkpt ID	Unique ID issued to the checkpoint at its creation.

show isis checkpoint lsp

To display the Intermediate System-to-Intermediate System (IS-IS) checkpoint link-state packet (LSP) protocol data unit (PDU) identifier database, use the show isis checkpoint lsp command in EXEC mode.

show isis [instance instance-id] checkpoint lsp

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS checkpoint LSPs for the specified instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays IS-IS checkpoint LSPs for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The checkpointed LSPs displayed by this command are used to restore the LSP database during a Cisco-proprietary nonstop forwarding (NSF) restart. The show isis checkpoint lsp command, with the show isis database command, may be used to verify the consistency of the two databases.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis checkpoint lsp command:


  RP/0/RSP0/CPU0:router# 
               show isis checkpoint lsp
             
  
  Level  LSPID              Chkpt ID 
  1      router-gsr6.00-00  80011f9c 
  1      router-gsr6.01-00  80011f88 
  1      router-gsr8.00-00  80011f74 
  1      router-gsr9.00-00  80011f60 
  2      router-gsr6.00-00  80011f4c 
  2      router-gsr6.01-00  80011f38 
  2      router-gsr8.00-00  80011f24 
  2      router-gsr9.00-00  80011f10 
  Total LSP count: 8 (L1: 4, L2 4, local L1: 2, local L2 2)

This table describes the significant fields shown in the display.

Table 8. show isis checkpoint lsp Field Descriptions
Field	Description
Level	Routers with Level 1 or Level 2 adjacency configured.
LSPID	LSP identifier. The first six octets form the system ID of the router that originated the LSP. The next octet is the pseudonode ID. When this byte is 0 , the LSP describes links from the system. When it is nonzero, the LSP is a so-called nonpseudonode LSP. This is similar to a router link-state advertisement (LSA) in the Open Shortest Path First (OSPF) protocol. The LSP describes the state of the originating router. For each LAN, the designated router for that LAN creates and floods a pseudonode LSP, describing all systems attached to that LAN. The last octet is the LSP number. If there is more data than can fit in a single LSP, the LSP is divided into multiple LSP fragments. Each fragment has a different LSP number. An asterisk (*) indicates that the LSP was originated by the system on which this command is issued.
Chkpt ID	Unique ID issued to the checkpoint at its creation.

Related Commands


Command	Description
show isis checkpoint adjacency	Displays the IS-IS checkpoint adjacency database.
show isis database	Displays the IS-IS link-state database.

show isis database

To display the Intermediate System-to-Intermediate System (IS-IS) link-state packet (LSP) database, use the show isis database command in EXEC mode.

show isis [instance instance-id] database [level {1 | 2}] [update] [summary] [detail] [verbose] [* | lsp-id]

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS LSP database for the specified instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.
level { 1 \| 2 }	(Optional) Displays the IS-IS LSP database for Level 1 or Level 2 independently.
update	(Optional) Displays contents of LSP database managed by update thread.
summary	(Optional) Displays the LSP ID number, sequence number, checksum, hold time, and bit information.
detail	(Optional) Displays the contents of each LSP.
verbose	(Optional) Displays the contents of each LSP.
* \| `lsp-id`	(Optional) LSP protocol data units (PDUs) identifier. Displays the contents of a single LSP by its ID number or may contain an * as a wildcard character.

Command Default

No instance ID specified displays the IS-IS LSP database for all the IS-IS instances.

Both Level 1 and Level 2 is configured if no level is specified.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

Each of the options for the show isis database command can be entered in an arbitrary string within the same command entry. For example, the following are both valid command specifications and provide the same output: show isis database detail level 2 and show isis database level 2 detail .

The summary keyword used with this command allows you to filter through a large IS-IS database and quickly identify problematic areas.

Task ID


Task ID	Operations
isis	read

show isis database-log

To display the entries in the Intermediate System-to-Intermediate System (IS-IS) database log, use the show isis database-log command in EXEC mode.

show isis database-log [level {1 | 2}] [last number | first number]

Syntax Description


level { 1 \| 2 }	(Optional) Displays the database log for Level 1 or Level 2 independently.
last `number`	(Optional) Specifies that the output be restricted to the last `number` of entries. Range is 1 to 1000.
first `number`	(Optional) Specifies that the output be restricted to the first `number` of entries. Range is 1 to 1000.

Command Default

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis database-log command:


  RP/0/RSP0/CPU0:router# show isis database-log 
  
     IS-IS 10 Level 1 Link State Database Log
                                    New LSP                 Old LSP
  WHEN     LSPID                Op  Seq Num    Holdtime OL  Seq Num    Holdtime OL
  01:17:19 12b1.03-00           REP 0x00000003 1200      0  0x00000002 340       0
  001:06:20 12b1.00-00          REP 0x000001d8 1200      0  0x000001d7 375       0
  01:06:00 12b1.03-00           REP 0x00000004 1200      0  0x00000003 520       0
  01:05:46 12a1.00-00           REP 0x000001fc 1200      0  0x000001fb 425       0
  00:55:01 12b1.00-00           REP 0x000001d9 1200      0  0x000001d8 520       0
  00:53:39 12b1.03-00           REP 0x00000005 1200      0  0x00000004 459       0
  00:53:19 12a1.00-00           REP 0x000001fd 1200      0  0x000001fc 453       0
  00:42:12 12b1.00-00           REP 0x000001da 1200      0  0x000001d9 431       0
  00:39:56 12b1.03-00           REP 0x00000006 1200      0  0x00000005 376       0
  00:38:54 12a1.00-00           REP 0x000001fe 1200      0  0x000001fd 334       0
  00:29:10 12b1.00-00           REP 0x000001db 1200      0  0x000001da 418       0
  00:27:22 12b1.03-00           REP 0x00000007 1200      0  0x00000006 446       0
  00:25:10 12a1.00-00           REP 0x000001ff 1200      0  0x000001fe 375       0
  00:17:04 12b1.00-00           REP 0x000001dc 1200      0  0x000001db 473

This table describes the significant fields shown in the display.

Table 9. show isis database-log Field Descriptions
Field	Description
WHEN	Elapsed time (in hh:mm:ss) since the event was logged.
LSPID	LSP identifier. The first six octets form the system ID of the router that originated the LSP. The next octet is the pseudonode ID. When this byte is 0 , the LSP describes links from the system. When it is nonzero, the LSP is a so-called nonpseudonode LSP. This is similar to a router link-state advertisement (LSA) in the Open Shortest Path First (OSPF) protocol. The LSP describes the state of the originating router. For each LAN, the designated router for that LAN creates and floods a pseudonode LSP, describing all systems attached to that LAN. The last octet is the LSP number. If there is more data than can fit in a single LSP, the LSP is divided into multiple LSP fragments. Each fragment has a different LSP number. An asterisk (*) indicates that the LSP was originated by the system on which this command is issued.
New LSP	New router or pseudonode appearing in the topology.
Old LSP	Old router or pseudonode leaving the topology.
Op	Operation on the database: inserted (INS) or replaced (REP).
Seq Num	Sequence number for the LSP that allows other systems to determine if they have received the latest information from the source.
Holdtime	Time the LSP remains valid (in seconds). An LSP hold time of 0 indicates that this LSP was purged and is being removed from the link-state database (LSDB) of all routers. The value indicates how long the purged LSP stays in the LSDB before being completely removed.
OL	Overload bit. Determines if the IS is congested. If the Overload bit is set, other routers do not use this system as a transit router when calculating routers. Only packets for destinations directly connected to the overloaded router are sent to this router.

Related Commands


Command	Description
show isis database	Displays the IS-IS link-state packet (LSP) database.

show isis fast-reroute

To display per-prefix LFA information, use the show isis fast-reroute command in EXEC mode.

show isis fast-reroute A.B.C.D/length | detail | summary | sr-only

Syntax Description


`A.B.C.D/length`	Network to show per-prefix LFA information.
detail	Use to display tiebreaker information about the backup.
summary	Use to display the number of prefixes having protection per priority.
sr-only	Use to display SR-labeled prefixes only.

Command Default

None

Command History


Release	Modification
Release 4.0.1	This command was introduced.
Release 6.3.2	The sr-only keyword was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from show isis fast-reroute command that displays per-prefix LFA information:


RP/0/RSP0/CPU0:router# show isis fast-reroute 10.1.6.0/24

L1 10.1.6.0/24 [20/115]
     via 10.3.7.47, POS0/3/0/1, router2
       FRR backup via 10.1.7.145, GigabitEthernet0/1/0/3, router3

The following is sample output from show isis fast-reroute detail command that displays tie-breaker information about the backup:


RP/0/RSP0/CPU0:router# show isis fast-reroute 10.1.6.0/24 detail 

L1 10.1.6.0/24 [20/115] low priority
     via 10.3.7.47, POS0/3/0/1, router2
       FRR backup via 10.1.7.145, GigabitEthernet0/1/0/3, router3
       P: No, TM: 30, LC: Yes, NP: No, D: No
     src router2.00-00, 192.168.0.47
   L2 adv [20] native, propagated

The following is sample output from show isis fast-reroute summary command that displays the number of prefixes having protection per priority:


RP/0/RSP0/CPU0:router#show isis fast-reroute summary
IS-IS frr IPv4 Unicast FRR summary

                                      Critical   High       Medium     Low        Total     
                                      Priority   Priority   Priority      Priority             
Prefixes reachable in L1
  All paths protected     0              0             2                8               10        
  Some paths protected 0              0             1                3               4         
  Unprotected                0              0             1                3               4         
  Protection coverage    0.00%     0.00%     75.00%     78.57%     77.78%    
Prefixes reachable in L2
  All paths protected     0              0             0               0                0         
  Some paths protected 0              0             1               0                1         
  Unprotected                0              0             0               0                0         
  Protection coverage    0.00%     0.00%     100.00%   0.00%      100.00%

The following is sample output from show isis fast-reroute sr-only command that displays fast-reroute repair paths for prefixes associated with a segment routing prefix SID:


RP/0/RSP0/CPU0:router#show isis fast-reroute sr-only
IS-IS 1 IPv4 Unicast FRR backups

Codes: L1 - level 1, L2 - level 2, ia - interarea (leaked into level 1)
       df - level 1 default (closest attached router), su - summary null
       C - connected, S - static, R - RIP, B - BGP, O - OSPF
       E - EIGRP, A - access/subscriber, M - mobile, a - application
       i - IS-IS (redistributed from another instance)
       D - Downstream, LC - Line card disjoint, NP - Node protecting
       P - Primary path, SRLG - SRLG disjoint, TM - Total metric via backup

Maximum parallel path count: 8

L2 20.1.0.101/32 [10/115]
     via 10.1.1.101, GigabitEthernet0/0/0/2, r101, SRGB Base: 16000, Weight: 0
         Backup path: TI-LFA (link), via 10.4.1.103, GigabitEthernet0/0/0/1 r103, SRGB Base: 16000, Weight: 0
           P node: r103.00 [20.1.0.103], Label: ImpNull
           Q node: r102.00 [20.1.0.102], Label: 24001
           Prefix label: 16101
           Backup-src: r101.00
L2 20.1.0.102/32 [30/115]
     via 10.1.1.101, GigabitEthernet0/0/0/2, r101, SRGB Base: 16000, Weight: 0
         Backup path: TI-LFA (link), via 10.4.1.103, GigabitEthernet0/0/0/1 r103, SRGB Base: 16000, Weight: 0
           P node: r103.00 [20.1.0.103], Label: ImpNull
           Q node: r102.00 [20.1.0.102], Label: 24001
           Prefix label: ImpNull
           Backup-src: r102.00
L2 20.1.0.103/32 [20/115]
     via 10.4.1.103, GigabitEthernet0/0/0/1, r103, SRGB Base: 16000, Weight: 0
         Backup path: TI-LFA (link), via 10.1.1.101, GigabitEthernet0/0/0/2 r101, SRGB Base: 16000, Weight: 0
           P node: r102.00 [20.1.0.102], Label: 16102
           Q node: r103.00 [20.1.0.103], Label: 24001
           Prefix label: ImpNull
           Backup-src: r103.00

show isis hostname

To display the entries in the Intermediate System-to-Intermediate System (IS-IS) router name-to-system ID mapping table, use the show isis hostname command in EXEC mode.

show isis [instance instance-id] hostname

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS router name-to-system ID mapping table for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays the IS-IS router name-to-system ID mapping table for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The show isis hostname command does not display entries if the dynamic hostnames are disabled.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis hostname command with the instance and instance-id values specified:


  RP/0/RSP0/CPU0:router# show isis instance isp hostname
  
  ISIS isp hostnames
      Level  System ID      Dynamic Hostname
       1     0001.0000.0005 router 
       2   * 0001.0000.0011 router-11

This table describes the significant fields shown in the display.

Table 10. show isis instance isp hostname Field Descriptions
Field	Description
Level	IS-IS level of the router.
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Dynamic Hostname	Hostname of the router.
*	Local router.

Related Commands


Command	Description
hostname	Specifies the name of the local router.
hostname dynamic disable	Enables the IS-IS routing protocol to dynamically update the mapping of router names to system IDs.

show isis interface

To display information about the Intermediate System-to-Intermediate System (IS-IS) interfaces, use the show isis interface command in EXEC mode.

show isis interface [type interface-path-id | level {1 | 2}] [brief]

Syntax Description

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

level { 1 | 2 }

(Optional) Displays IS-IS interface information for Level 1 or Level 2 independently.

brief

(Optional) Displays brief interface output.

Command Default

Displays all IS-IS interfaces.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis interface command:


  RP/0/RSP0/CPU0:router#show isis interface 
            GigabitEthernet 0/3/0/2
   Gi /3/0/2                  Enabled
    Adjacency Formation:      Enabled
    Prefix Advertisement:     Enabled
    BFD:                      Disabled
    BFD Min Interval:         150
    BFD Multiplier:           3
    
    Circuit Type:             level-2-only
    Media Type:               P2P
    Circuit Number:           0
    Extended Circuit Number:  67111168
    Next P2P IIH in:          4 s
    LSP Rexmit Queue Size:    0
    
    Level-2                   
      Adjacency Count:        1
      LSP Pacing Interval:    33 ms
      PSNP Entry Queue Size:  0
    
    CLNS I/O
      Protocol State:         Up
      MTU:                    4469
    
    IPv4 Unicast Topology:    Enabled
      Adjacency Formation:    Running
      Prefix Advertisement:   Running
      Metric (L1/L2):         10/100
      MPLS LDP Sync (L1/L2):  Disabled/Disabled
    IPv6 Unicast Topology:    Disabled (Not cfg on the intf)
    
    IPv4 Address Family:      Enabled
      Protocol State:         Up
      Forwarding Address(es): 10.3.10.143
      Global Prefix(es):      10.3.10.0/24
    IPv6 Address Family:      Disabled (No topology enabled which uses IPv6)
    
    LSP transmit timer expires in 0 ms
    LSP transmission is idle
    Can send up to 9 back-to-back LSPs in the next 0 ms

This table describes the significant fields shown in the display.

Table 11. show isis interface Field Descriptions
Field	Description
GigabitEthernet0/6/0/0	Status of the interface, either enabled or disabled.
Adjacency formation	Status of adjacency formation, either enabled or disabled.
Prefix Advertisement	Status of advertising connected prefixes, either enabled or disabled.
BFD	Status of Bidirectional Forwarding Detection (BFD), either enabled or disabled.
BFD Min Interval	BFD minimum interval.
BFD Multiplier	BFD multiplier.
Circuit Type	Levels the interface is running on (circuit-type configuration) which may be a subset of levels on the router.
Media Type	Media type on which IS-IS is running.
Circuit Number	Unique ID assigned to a circuit internally (8-bit integer).
Extended Circuit Number	Valid only for point-to-point interfaces (32-bit integer).
LSP Rexmit Queue Size	Number of LSPs pending retransmission on the interface.
Adjacency Count	Number of adjacencies formed with a neighboring router that supports the same set of protocols.
PSNP Entry Queue Size	Number of SNP entries pending inclusion in the next PSNP.
LAN ID	ID of the LAN.
Priority (Local/DIS)	Priority of this interface or priority of the Designated Intermediate System.
Next LAN IIH in	Time (in seconds) in which the next LAN hello message is sent.
LSP Pacing Interval	Interval at which the link-state packet (LSP) transmission rate (and by implication the reception rate of other systems) is to be reduced.
Protocol State	Running state of the protocol (up or down).
MTU	Link maximum transmission unit (MTU).
SNPA	Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
All Level-n ISs	Status of interface membership in Layer 2 multicast group. The status options are Yes or reason for not being a member of the multicast group.
IPv4 Unicast Topology	Status of the topology, either enabled or disabled.
Adjacency Formation	Status of adjacency formation. The status options are Running or a reason for not being ready to form adjacencies.
Prefix Advertisement	Status of advertising prefixes, either enabled or disabled.
Metric (L1/L2)	IS-IS metric for the cost of the adjacency between the originating router and the advertised neighbor, or the metric of the cost to get from the advertising router to the advertised destination (which can be an IP address, an end system (ES), or a connectionless network service (CLNS) prefix).
MPLS LDP Sync (L1/L2)	Status of LDP IS-IS synchronization, either enabled or disabled. When enabled, the state of synchronization (Sync Status) is additionally displayed as either achieved or not achieved.
IPv4 Address Family	Status of the address family, either enabled or disabled.
Protocol State	State of the protocol.
Forwarding Address(es)	Addresses on this interface used by the neighbor for next-hop forwarding.
Global Prefix(es)	Prefixes for this interface included in the LSP.
LSP transmit timer expires in	LSP transmission expiration timer interval (in milliseconds).
LSP transmission is	State of LSP transmission. Valid states are idle in progress requested requested and in progress

The following is sample output from the show isis interface command with the brief keyword:


  RP/0/0/CPU0:router# show isis interface brief
  
      Interface      All     Adjs    Adj Topos  Adv Topos  CLNS   MTU    Prio
                     OK    L1   L2    Run/Cfg    Run/Cfg                L1   L2
  -----------------  ---  ---------  ---------  ---------  ----  ----  --------
  PO0/5/0/0          Yes    1    1      1/1        1/1     Up    4469    -    -
  Gi0/6/0/0          Yes    1*   1*     1/1        1/1     Up    1497   64   64

This table describes the significant fields shown in the display.

Table 12. show isis interface brief Field Descriptions
Field	Description
Interface	Name of the interface.
All OK	Everything is working as expected for this interface.
Adjs L1 L2	Number of L1 and L2 adjacencies over this interface.
Adj Topos Run/Cfg	Number of topologies that participate in forming adjacencies. Number of topologies that were configured to participate in forming adjacencies.
Adv Topos Run/Cfg	Number of topologies that participate in advertising prefixes. Number of topologies that were configured to participate in advertising prefixes.
CLNS	Status of the Connectionless Network Service. Status options are Up or Down.
MTU	Maximum transfer unit size for the interface.
Prio L1 L2	Interface L1 priority. Interface L2 priority.

show isis lsp-log

To display link-state packet (LSP) log information, use the show isis lsp-log command in EXEC mode.

show isis [instance instance-id] lsp-log [level {1 | 2}] [last number | first number]

Syntax Description


instance `instance-id`	(Optional) Displays the LSP log information for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.
level { 1 \| 2 }	(Optional) Displays the Intermediate System-to-Intermediate System (IS-IS) link-state database for Level 1 or Level 2 independently.
last `number`	(Optional) Specifies that the output be restricted to the last `number` of entries. Range is 1 to 20.
first `number`	(Optional) Specifies that the output be restricted to the first `number` of entries. Range is 1 to 20.

Command Default

No instance ID specified displays the LSP log information for all the IS-IS instances.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis lsp-log command with the instance and instance-id values specified:


  RP/0/RSP0/CPU0:router# show isis instance isp lsp-log 
  
  ISIS isp Level 1 LSP log
    When       Count      Interface       Triggers
  00:02:36         1                      
  00:02:31         1                      LSPREGEN
  00:02:26         1      PO4/1           DELADJ
  00:02:24         1      PO4/1           NEWADJ
  00:02:23         1      Gi5/0           DIS
  00:01:27         1      Lo0             IPDOWN
  00:01:12         1      Lo0             IPUP
  
  
  ISIS isp Level 2 LSP log
    When       Count      Interface       Triggers
  00:02:36         1 
  00:02:30         1                      LSPREGEN
  00:02:26         1      PO4/1           DELADJ
  00:02:24         1      PO4/1           NEWADJ
  00:02:23         1      Gi5/0           DIS
  00:02:21         1                      AREASET
  00:01:27         1      Lo0             IPDOWN
  00:01:12         1      Lo0             IPUP

This table describes the significant fields shown in the display.

Table 13. show isis instance isp lsp-log Field Descriptions
Field	Description
Level	IS-IS level of the router.
When	How long ago (in hh:mm:ss) an LSP rebuild occurred. The last 20 occurrences are logged.
Count	Number of events that triggered this LSP run. When there is a topology change, often multiple LSPs are received in a short period. A router waits 5 seconds before running a full LSP, so it can include all new information. This count denotes the number of events (such as receiving new LSPs) that occurred while the router was waiting its 5 seconds before running full LSP.
Interface	Interface that corresponds to the triggered reasons for the LSP rebuild.
Triggers	A list of all reasons that triggered an LSP rebuild. The triggers are AREASET—area set changed ATTACHFLAG—bit attached CLEAR— clear command CONFIG—configuration change DELADJ—adjacency deleted DIS—DIS changed IFDOWN—interface down IPADDRCHG—IP address change IPDEFORIG—IP def-orig IPDOWN—connected IP down IFDOWN—interface down IPEXT—external IP IPIA—nterarea IP IPUP—connected IP up LSPDBOL—LSPDBOL bit LSPREGEN—LSP regeneration NEWADJ— new adjacency

show isis mesh-group

To display Intermediate System-to-Intermediate System (IS-IS) mesh group information, use the show isis mesh-group command in EXEC mode.

show isis [instance instance-id] mesh-group

Syntax Description


instance `instance-id`	(Optional) Displays the mesh group information for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays the IS-IS mesh group information for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis mesh-group command with the instance and instance-id values specified:


 RP/0/RSP0/CPU0:router# show isis instance isp mesh-group 
  
  ISIS isp Mesh Groups
  
  Mesh group 6:
  GigabitEthernet 0/4/0/1

This table describes the significant fields shown in the display.

Table 14. show isis instance isp mesh-group Field Descriptions
Field	Description
Mesh group	Mesh group number to which this interface is a member. A mesh group optimizes link-state packet (LSP) flooding in nonbroadcast multiaccess (NBMA) networks with highly meshed, point-to-point topologies. LSPs that are first received on interfaces that are part of a mesh group are flooded to all interfaces except those in the same mesh group.
GigabitEthernet0/4/0/1	Interface belonging to mesh group 6.

show isis mpls traffic-eng adjacency-log

To display a log of Multiprotocol Label Switching traffic engineering (MPLS TE) adjacency changes for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis mpls traffic-eng adjacency-log command in EXEC mode.

show isis [instance instance-id] mpls traffic-eng adjacency-log [last number | first number]

Syntax Description


instance `instance-id`	(Optional) Displays the MPLS TE adjacency changes for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.
last `number`	(Optional) Specifies that the output is restricted to last `number` of entries. Range is 1 to 20.
first `number`	(Optional) Specifies that the output is restricted to first `number` of entries. Range is 1 to 20.

Command Default

No instance ID specified displays MPLS TE adjacency changes for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the show isis mpls traffic-eng adjacency-log command to display the status of MPLS TE adjacencies.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis mpls traffic-eng adjacency-log command with the instance and instance-id values specified:


  RP/0/RSP0/CPU0:router# show isis instance isp mpls traffic-eng adjacency-log 
  
  IS-IS isp Level-2 MPLS Traffic Engineering adjacency log
  When      Neighbor ID        IP Address       Interface Status
  00:03:36  router-6           172.17.1.6         PO0/3/0/1 Up     
  00:03:36  router-6           172.17.1.6         PO0/3/0/1 Down     
  00:02:38  router-6           172.17.1.6         PO0/3/0/1 Up

This table describes the significant fields shown in the display.

Table 15. show isis instance isp mpls traffic-eng adjacency-log Field Descriptions
Field	Description
When	Time (in hh:mm:ss) since the entry was recorded in the log.
Neighbor ID	Identification value of the neighbor.
IP Address	Neighbor IP Version 4 (IPv4) address.
Interface	Interface from which a neighbor is learned.
Status	Up (active) or Down (disconnected).

Related Commands


Command	Description
show isis mpls traffic-eng advertisements	Displays the last flooded record from MPLS traffic engineering.

show isis mpls traffic-eng advertisements

To display the latest flooded record from Multiprotocol Label Switching traffic engineering (MPLS TE) for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis mpls traffic-eng advertisements command in EXEC mode.

show isis [instance instance-id] mpls traffic-eng advertisements

Syntax Description


instance `instance-id`	(Optional) Displays the latest flooded record from MPLS TE for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays the latest flooded record from MPLS TE for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the show isis mpls traffic-eng advertisements command to verify that MPLS TE is flooding its record and that the bandwidths are correct.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis mpls traffic-eng advertisements command with the instance and instance-id values specified:


 RP/0/RSP0/CPU0:router# show isis instance isp mpls traffic-eng advertisements 
  
  ISIS isp Level-2 MPLS Traffic Engineering advertisements
        System ID: router-9
        Router ID: 172.18.0.9
        Link Count: 1
          Link[0]
            Neighbor System ID: router-gsr6 (P2P link)
            Interface IP address: 172.18.0.9
            Neighbor IP Address: 172.18.0.6
            Admin. Weight: 0
            Physical BW: 155520000 bits/sec
            Reservable BW global: 10000000 bits/sec
            Reservable BW sub: 0 bits/sec
            Global pool BW unreserved: 
              [0]: 10000000 bits/sec, [1]: 10000000 bits/sec
              [2]: 10000000 bits/sec, [3]: 10000000 bits/sec
              [4]: 10000000 bits/sec, [5]: 10000000 bits/sec
              [6]: 10000000 bits/sec, [7]: 10000000 bits/sec
            Sub pool BW unreserved: 
              [0]: 0 bits/sec, [1]: 0 bits/sec
              [2]: 0 bits/sec, [3]: 0 bits/sec
              [4]: 0 bits/sec, [5]: 0 bits/sec
              [6]: 0 bits/sec, [7]: 0 bits/sec
            Affinity Bits: 0x00000000

This table describes the significant fields shown in the display.

Table 16. show isis instance isp mpls traffic-eng advertisements Field Descriptions
Field	Description
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or if the hostname dynamic disable command has been executed, the 6-octet system ID is used.
Router ID	MPLS TE router ID.
Link Count	Number of links that MPLS TE advertised.
Neighbor System ID	System ID of a neighbor number in an area. The six bytes directly preceding the n-selector are the system ID. The system ID length is a fixed size and cannot be changed. The system ID must be unique throughout each area (Level 1) and throughout the backbone (Level 2). In an IS-IS routing domain, each router is represented by a 6-byte hexadecimal system ID. When network administrators maintain and troubleshoot networking devices, they must know the router name and corresponding system ID.
Interface IP address	IP address of the interface.
Neighbor IP Address	IP address of the neighbor.
Admin. Weight	Administrative weight associated with this link.
Physical BW	Link bandwidth capacity (in bits per second).
Reservable BW	Reservable bandwidth on this link.
Global pool BW unreserved	Unreserved bandwidth that is available in the global pool.
Sub pool BW unreserved	Amount of unreserved bandwidth that is available in the subpool.
Affinity Bits	Link attribute flags being flooded. Bits are MPLS-TE specific.

Related Commands


Command	Description
show isis mpls traffic-eng adjacency-log	Displays a log of MPLS TE adjacency changes for IS-IS.

show isis neighbors

To display information about Intermediate System-to-Intermediate System (IS-IS) neighbors, use the show isis neighbors command in EXEC mode.

show isis [instance instance-id] neighbors [type interface-path-id | summary] [detail] [systemid system-id]

Syntax Description

instance instance-id

(Optional) Displays the IS-IS neighbor information for the specified IS-IS instance only.

The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

summary

(Optional) Displays neighbor status count for each level.

detail

(Optional) Displays additional details.

systemid system-id

(Optional) Displays the information for the specified neighbor only.

Command Default

No instance ID specified displays neighbor information for all the IS-IS instances.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis neighbors command with the instance and instance-id values specified:


  Total neighbor count: 3
  RP/0/RSP0/CPU0:router# show isis instance isp neighbors detail
  
  IS-IS isp neighbors:
  System Id      Interface        SNPA           State Holdtime Type IETF-NSF
  e222e          Gi0/1/0/0        *PtoP*         Up    23       L1   Capable 
    Area Address(es): 00
    IPv4 Address(es): 10.1.0.45*
    IPv6 Address(es): fe80::212:daff:fe6b:68a8*
      Topologies: 'IPv4 Unicast' 
    Uptime: 01:09:44
    IPFRR: LFA Neighbor: elise
           LFA IPv4 address: 10.100.1.2
           LFA Router address: 192.168.0.45
  e333e Gi0/1/0/0.1      0012.da6b.68a8 Up    8        L1   Capable 
  e333e          Gi0/1/0/0.1      0012.da6b.68a8 Up    8        L1   Capable 
    Area Address(es): 00
    IPv4 Address(es): 10.100.1.2*
    Topologies: 'IPv4 Unicast'
    Uptime: 01:09:46
    IPFRR: LFA Neighbor: elise
           LFA IPv4 address: 10.1.0.45
           LFA Router address: 192.168.0.45
           LFA Interface: Gi0/1/0/0
  m44i           Gi0/1/0/1        0012.da62.e0a8 Up    7        L1   Capable 
    Area Address(es): 00 11
    IPv4 Address(es): 10.1.2.47*
    IPv6 Address(es): fe80::212:daff:fe62:e0a8*
      Topologies: 'IPv4 Unicast'
    Uptime: 01:09:33
   
  Total neighbor count: 3

This table describes the significant fields shown in the display.

Table 17. show isis instance isp neighbors Field Descriptions
Field	Description
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Interface	Interface through which the neighbor is reachable.
SNPA	Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
State	Adjacency state of the neighboring interface. Valid states are: Down, Init, and Up.
Holdtime	Hold time of the neighbor.
Type	Type of adjacency.
IETF-NSF	Specifies whether the neighbor can adhere to the IETF-NSF restart mechanism. Valid states are Capable and Unable.
Area Address(es)	Number of area addresses on this router.
IPv4 Address(es)	IPv4 addresses configured on this router.
Topologies	Address and subaddress families for which IS-IS is configured.
Uptime	Time (in hh:mm:ss) that the neighbor has been up.
IPFRR: LFA Neighbor	IP fast reroute (IPFRR) loop-free alternate (LFA) neighbor.
LFA IPv4 address:	Address of the LFA.
LFA Interface:	LFA interface.

The following is sample output from the show isis neighbors command with the summary keyword specified:


  RP/0/RSP0/CPU0:router# show isis instance isp neighbors summary
  
  ISIS isp neighbor summary:
      State         L1       L2     L1L2
      Up             0        0        2
      Init           0        0        0
      Failed         0        0        0

This table describes the significant fields shown in the display.

Table 18. show isis neighbors summary Field Descriptions
Field	Description
State	State of the neighbor is up, initialized, or failed.
L1	Number of Level 1 neighbors.
L2	Number of Level 2 neighbors.
L1L2	Number of Level 1 and 2 neighbors.

Related Commands


Command	Description
show isis adjacency	Displays IS-IS adjacencies.

show isis protocol

To display summary information about an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis protocol command in EXEC mode.

show isis [instance instance-id] protocol

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS adjacencies for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.

Command Default

No instance ID specified displays IS-IS adjacencies for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis protocol command:


  Router# show isis protocol 
  
  IS-IS Router: isp
        System Id: 0001.0000.0011
        IS Levels: level-1-2
        Manual area address(es):
          49
  
        Routing for area address(es):
          49
        Non-stop forwarding: Cisco Proprietary NSF Restart enabled
        Process startup mode: Cold Restart
        Topologies supported by IS-IS:
          IPv4 Unicast
            Level-1 iSPF status: Dormant (awaiting initial convergence)
                Level-2 iSPF status: Dormant (awaiting initial convergence)
            No protocols redistributed
            Distance: 115
        Interfaces supported by IS-IS:
          Loopback0 is running passively (passive in configuration)
          GigabitEthernet 0/4/0/1 is running actively (active in configuration)
          GigabitEthernet 0/5/0/1 is running actively (active in configuration)

This table describes the significant fields shown in the display.

Table 19. show isis protocol Field Descriptions
Field	Description
System ID:	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
IS Levels:	IS-IS level of the router.
Manual area address(es)	Area addresses that are manually configured.
Routing for areaaddress(es)	Area addresses for which this router provides the routing.
Non-stop forwarding:	Status and name of nonstop forwarding (NSF).
Process startup mode:	Mode in which the last process startup occurred. Valid modes are: Cisco Proprietary NSF Restart IETF NSF Restart Cold Restart
iSPF status:	State of incremental shortest path first (iSPF) configuration for this IS-IS instance. Four states exist: Disabled if iSPF has not been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm. Dormant if iSPF has been configured but is awaiting initial convergence before initializing. Awake if iSPF has been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm. Active if IS-IS is ready to consider using the iSPF algorithm whenever a new route calculation needs to be run.
No protocols redistributed:	No redistributed protocol information exists to be displayed.
Distance:	Administrative distance for this protocol.

show isis route

To display IP reachability information for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis route command in EXEC mode.

show isis [instance instance-id] [ipv4 | ipv6 | afi-all] [unicast | multicast [topology {all | topo-name}] | safi-all] route [ip-address mask | ip-address/ length [longer-prefixes]] [summary] [multicast-intact] [backup] [detail] [sr-only]

Syntax Description


instance `instance-id`	(Optional) Displays the IP reachability information for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.
ipv4	(Optional) Specifies IP Version 4 address prefixes.
ipv6	(Optional) Specifies IP Version 6 address prefixes.
afi-all	(Optional) Specifies all address prefixes.
unicast	(Optional) Specifies unicast address prefixes.
multicast	(Optional) Specifies multicast address prefixes.
topology	(Optional) Specifies IS-IS paths to intermediate systems.
all	(Optional) Specifies all topologies.
topology `topo-name`	(Optional) Specifies topology table information and name of the topology table.
safi-all	(Optional) Specifies all secondary address prefixes.
`ip-address`	(Optional) Network IP address about which routing information should be displayed.
`mask`	(Optional) Network mask specified in either of two ways: Network mask can be a four-part, dotted decimal address. For example, 255.0.0.0 indicates that each bit equal to 1 means the corresponding address bit is a network address. Network mask can be indicated as a slash (/) and number. For example, /8 indicates that the first 8 bits of the mask are ones, and the corresponding bits of the address are the network address.
`/` `length`	(Optional) Length of the IP prefix. A decimal value that indicates how many of the high-order contiguous bits of the address compose the prefix (the network portion of the address). A slash must precede the decimal value. Range is 0 to 32.
longer-prefixes	(Optional) Displays route and more-specific routes.
summary	(Optional) Displays topology summary information.
multicast-intact	(Optional) Displays multicast intact information for this entry.
systemid	(Optional) Displays multicast information by system ID.
backup	(Optional) Displays information about ISIS routes not selected for installation in the RIB.
detail	(Optional) Displays link-state packet (LSP) details.
sr-only	(Optional) Displays SR-labeled prefixes only.

Command Default

No instance ID specified displays the IP reachability information for all the IS-IS instances.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added.
Release 6.3.2	The sr-only keyword was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis route command:


  RP/0/RSP0/CPU0:router# show isis route
  
  IS-IS isp IPv4 Unicast routes 
  Codes: L1 - level 1, L2 - level 2, ia - interarea (leaked into level 1)
  df - level 1 default (closest attached router), su - summary null
  C - connected, S - static, R - RIP, B - BGP, O - OSPF
  i - IS-IS (redistributed from another instance) 
  
  Maximum parallel path count: 8 
  
  L2 10.76.240.6/32 [4/115]
  via 10.76.245.252, SRP0/1/0/2, isp2
  via 10.76.246.252, SRP0/1/0/0, isp2
  C 10.76.240.7/32
  is directly connected, Loopback0
  L2 10.76.240.9/32 [256/115]
  via 10.76.249.2, GigabitEthernet 0/3/0/0, isp3
  L2 10.76.240.10/32 [296/115]
  via 10.76.249.2, GigabitEthernet 0/3/0/0, isp3
  C 10.76.245.0/24
  is directly connected, SRP0/1/0/2
  C 10.76.246.0/24
  is directly connected, SRP0/1/0/0
  C 10.76.249.0/26
  is directly connected, GigabitEthernet 0/3/0/0
  L2 10.101.10.0/24 [296/115]
  via 10.76.249.2, GigabitEthernet 0/3/0/0, isp3

This table describes the significant fields shown in the display.

Table 20. show isis route ipv4 unicast Field Descriptions
Field	Description
C172.18.0.0/24	Connected route for GigabitEthernet interface 0/5/0/0.
C 172.19.1.0/24	Connected route for GigabitEthernet interface 0/4/0/1.
L1 172.35.0.0/24 [10]	Level 1 route to network 172.35.0.0/24.
C 172.18.0/24	Connected route for loopback interface 0.

This is sample output from the show isis route command with sr-only keyword that shows only routes associated with a segment routing prefix SID:


RP/0/RSP0/CPU0:router# show isis route sr-only

IS-IS 1 IPv4 Unicast routes

Codes: L1 - level 1, L2 - level 2, ia - interarea (leaked into level 1)
       df - level 1 default (closest attached router), su - summary null
       C - connected, S - static, R - RIP, B - BGP, O - OSPF
       E - EIGRP, A - access/subscriber, M - mobile, a - application
       i - IS-IS (redistributed from another instance)

Maximum parallel path count: 8

C  20.1.0.100/32
     is directly connected, Loopback0
L2 20.1.0.101/32 [10/115]
     via 10.1.1.101, GigabitEthernet0/0/0/2, r101, SRGB Base: 16000, Weight: 0
L2 20.1.0.102/32 [30/115]
     via 10.1.1.101, GigabitEthernet0/0/0/2, r101, SRGB Base: 16000, Weight: 0
L2 20.1.0.103/32 [20/115]
     via 10.4.1.103, GigabitEthernet0/0/0/1, r103, SRGB Base: 16000, Weight: 0

show isis spf-log

To display how often and why the router has run a full shortest path first (SPF) calculation, use the show isis spf-log command in EXEC mode.

show isis [ instance instance-id ] [ [ ipv4 | ipv6 | afi-all ] [ unicast | multicast [ topology { all | topo-name } ] | safi-all ] ] spf-log [ level { 1 | 2 } ] [ ispf | fspf | prc | nhc ] [ detail | verbose | plfrr | ppfrr ] [ last number | first number ]

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS SPF log for the specified IS-IS instance only.
ipv4	(Optional) Specifies IP Version 4 address prefixes.
ipv6	(Optional) Specifies IP Version 6 address prefixes.
afi-all	(Optional) Specifies all address prefixes.
unicast	(Optional) Specifies unicast address prefixes.
multicast	(Optional) Specifies multicast address prefixes.
topology all \| `topo-name`	(Optional) Specifies topology table information for all topologies or for the specified topology table ( `top-name` ).
safi-all	(Optional) Specifies all secondary address prefixes.
level { 1 \| 2 }	(Optional) Displays the IS-IS SPF log for Level 1 or Level 2 independently.
ispf	(Optional) Specifies incremental SPF entries only.
fspf	(Optional) Specifies full SPF entries only.
prc	(Optional) Specifies partial route calculations only.
nhc	(Optional) Specifies next-hop route calculations only.
detail	(Optional) Specifies detailed output. Includes a breakdown of the time taken to perform the calculation and changes resulting from the calculation.
verbose	(Optional) Specifies verbose output.
last `number`	(Optional) Specifies that the output is restricted to the last `number` of entries. Range is 1 to 210.
first `number`	(Optional) Specifies that the output is restricted to the first `number` of entries. Range is 1 to 210.

Command Default

No instance ID specified displays IS-IS adjacencies for all the IS-IS instances.

Both Level 1 and Level 2 are configured if no level is specified.

Displays all types of route calculation (not just fspf, ispf, and prc).

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis spf-log command:


 Router# show isis spf-log 
  
       IS-IS 1 Level 1 IPv4 Unicast Route Calculation Log
                   Time  Total Trig
  Timestamp   Type (ms)  Nodes Count First Trigger LSP Triggers
  ----------- ---- ----  ----- ----- ----- ------- --- --------
  --- Thurs Aug 19 2004 ---
  12:00:50.787  FSPF  1    1     3   ensoft-grs7.00-00 LSPHEADER TLVCODE
  12:00:52.846  FSPF  1    1     1   ensoft-grs7.00-00 LSPHEADER 
  12:00:56.049  FSPF  1    1     1   ensoft-grs7.00-00 TLVCODE
  12:01:02.620  FSPF  1    1     2   ensoft-grs7.00-00 NEWADJ LINKTLV
      
       IS-IS 1 Level 1 IPv4 Unicast Route Calculation Log
                   Time  Total Trig
  Timestamp   Type (ms)  Nodes Count First Trigger LSP Triggers
  ----------- ---- ----  ----- ----- ----- ------- --- --------
  --- Mon Aug 19 2004 ---
  12:00:50.790  FSPF  0    1     4   ensoft-grs7.00-00 LSPHEADER TLVCODE
  12:00:54.043  FSPF  1    1     2   ensoft-grs7.00-00 NEWADJ LSPHEADER
  12:00:55.922  FSPF  1    2     1   ensoft-grs7.00-00 NEWLSPO
  12:00:56.724  FSPF  1    13    1   ensoft-grs7.00-00 NEWLSPO

This table describes the significant fields shown in the display.

Table 21. show isis spf-log ipv4 unicast Field Descriptions
Field	Description
Level	IS-IS level of the router.
Timestamp	Time when the SPF calculation started.
Duration	Number of milliseconds taken to complete this SPF run. Elapsed time is wall clock time, not CPU time.
Nodes	Number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run.
Trig Count	Number of events that triggered this SPF run. When there is a topology change, often multiple link-state packets (LSPs) are received in a short time. Depending on the configuration of the spf-interval command, a router may wait for a fixed period of time before running a router calculation. This count denotes the number of triggering events that occurred while the router was waiting to run the calculation. For a full description of the triggering events, see List of Triggers.
First Trigger LSP	LSP ID stored by the router whenever a full SPF calculation is triggered by the arrival of a new LSP. The LSP ID can suggest the source of routing instability in an area. If multiple LSPs are causing an SPF run, only the LSP ID of the first received LSP is remembered.
Triggers	List of all reasons that triggered a full SPF calculation. For a list of possible triggers, see List of Triggers.

This table lists triggers of a full SPF calculation.

Table 22. List of Triggers
Trigger	Description
PERIODIC	Runs a full SPF calculation very 15 minutes.
NEWLEVEL	Configured new level (using is-type) on this router.
RTCLEARED	Cleared IS-IS topology on the router.
MAXPATHCHANGE	Changed IP maximum parallel path.
NEWMETRIC	Changed link metric.
ATTACHFLAG	Changed Level 2 Attach bit.
ADMINDIST	Configured another administrative distance for the IS-IS instance on this router.
NEWADJ	Created a new adjacency to another router.
DELADJ	Deleted adjacency.
BACKUP	Installed backup route.
SEEDISPF	Seed incremental SPF.
NEXTHOP	Changed IP next-hop address.
NEWLSP0	New LSP 0 appeared in the topology.
LSPEXPIRED	Some LSP in the link-state database (LSDB) has expired.
LSPHEADER	Changed important LSP header fields.
TLVCODE	Type, length, and value (TLV) objects code mismatch, indicating that different TLV objects are included in the newest version of an LSP.
LINKTV	Changed Link TLV content.
PREFIXTLV	Changed Prefix TLV content.
AREAADDRTLV	Changed Area address TLV content.
IP ADDRTLV	Changed IP address TLV content.
TUNNEL	Changed RRR tunnel.

The following is sample output from the show isis spf-log command with the first keyword specified:


  Router# show isis spf-log first 2
  
      IISIS isp Level 1 IPv4 Unicast Route Calculation Log
                   Time  Total Trig
  Timestamp   Type (ms)  Nodes Count First Trigger LSP   Triggers
    Mon Aug 16 2004
  19:25:35.140  FSPF  1    1     1             12a5.00-00 NEWLSP0
  19:25:35.646  FSPF  1    1     1                        NEWADJ 
      
      
     IISIS isp Level 2  IPv4 Unicast Route Calculation Log
                   Time  Total Trig
  Timestamp   Type (ms)  Nodes Count First Trigger LSP   Triggers
    Mon Aug 16 2004
  19:25:35.139  FSPF  1    1     1             12a5.00-00 NEWLSP0
  19:25:35.347  FSPF  1    1     2             12a5.00-00 NEWSADJ TLVCODE

This table describes the significant fields shown in the display.

Table 23. show isis spf-log first Field Descriptions
Field	Description
Level	IS-IS level of the router.
Timestamp	Time at which the SPF calculation started.
Type	Type of route calculation. The possible types are incremental SPF (iSPF),full SPF (FSPF), or partial route calculation (PRC).
Time (ms)	Number of milliseconds taken to complete this SPF run. Elapsed time is wall clock time, not CPU time.
Nodes	Number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run.
Trig Count	Number of events that triggered this SPF run. When there is a topology change, often multiple link-state packets (LSPs) are received in a short time. Depending on the configuration of the spf-interval command, a router may wait for a fixed period of time before running a router calculation. This count denotes the number of triggering events that occurred while the router was waiting to run the calculation. For a full description of the triggering events, see List of Triggers.
First Trigger LSP	LSP ID stored by the router whenever a full SPF calculation is triggered by the arrival of a new LSP. The LSP ID can suggest the source of routing instability in an area. If multiple LSPs are causing an SPF run, only the LSP ID of the first received LSP is remembered.
Triggers	List of all reasons that triggered a full SPF calculation. For a list of possible triggers, see List of Triggers.

The following is sample output from the show isis spf-log command with the detail keyword specified:


  Router# show isis spf-log detail
  
      IISIS isp Level 1 IPv4 Unicast Route Calculation Log
                   Time  Total Trig
  Timestamp   Type (ms)  Nodes Count First Trigger LSP   Triggers
    Mon Aug 16 2004
  19:25:35.140  FSPF  1    1     1             12a5.00-00 NEWLSP0
    Delay:              51ms (since first trigger)
    SPT Calculation
      CPU Time:         0ms
      Real Time:        0ms
    Prefix Updates
      CPU Time:         1ms
      Real Time:        1ms
    New LSP Arrivals:    0
    Next Wait Interval: 200ms
                                Results
                          Reach Unreach Total
     Nodes:                   1       0     1
     Prefixes (Items)
       Critical Priority:     0       0     0
       High Priority:         0       0     0 
       Medium Priority        0       0     0 
       Low Priority           0       0     0 
  
       All Priorities         0       0     0
     Prefixes (Routes)
       Critical Priority:     0       -     0
       High Priority:         0       -     0
       Medium Priority        0        -    0
       Low Priority:          0        -    0
  
       All Priorities         0        -    0

This table describes the significant fields shown in the display.

Table 24. show isis spf-log detail Field Descriptions
Field	Description
Level	IS-IS level of the router.
Timestamp	Time at which the SPF calculation started.
Type	Type of route calculation. The possible types are incremental ispf, full SPF (FSPF), or partial route calculation (PRC).
Time (ms)	Number of milliseconds taken to complete this SPF run. Elapsed time is wall clock time, not CPU time.
Nodes	Number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run.
Trig Count	Number of events that triggered this SPF run. When there is a topology change, often multiple link-state packets (LSPs) are received in a short time. Depending on the configuration of the spf-interval command, a router may wait for a fixed period of time before running a router calculation. This count denotes the number of triggering events that occurred while the router was waiting to run the calculation. For a full description of the triggering events, see List of Triggers.
First Trigger LSP	LSP ID stored by the router whenever a full SPF calculation is triggered by the arrival of a new LSP. The LSP ID can suggest the source of routing instability in an area. If multiple LSPs are causing an SPF run, only the LSP ID of the first received LSP is remembered.
Triggers	List of all reasons that triggered a full SPF calculation. For a list of possible triggers, see List of Triggers.
Delay	Two different delays exist: The delay between the time when the route calculation was first triggered and the time when it was run. The delay between the end of the last route calculation and the start of this one. This is used to verify that the SPF-interval timers are working correctly, and is only reported for calculations after the first delay.
CPU Time	Two different CPU times exist: CPU time (in milliseconds) taken to calculate the shortest path tree (SPT). CPU time (in milliseconds) taken to perform the prefix updates.
Real Time	Two different real times exist: Real time (in milliseconds) taken to calculate the shortest path tree (SPT). Real time (in milliseconds) taken to perform the prefix updates.
New LSP Arrivals	Number of LSP arrivals since the start of this route calculation.
Next Wait Interval	Enforced delay until the next route calculation can be run, based on the spf-interval command configuration.
Reach	Number of reachable nodes or prefixes.
Unreach	Number of unreachable nodes or prefixes.
Total	Total number of nodes or prefixes at various priorities.

Related Commands


Command	Description
spf-interval	Sets IS-IS throttling of shortest path first (SPF) calculations.

show isis statistics

To display Intermediate System-to-Intermediate System (IS-IS) traffic counters, use the show isis statistics command in EXEC mode.

show isis [instance instance-id] statistics [type interface-path-id]

Syntax Description

instance instance-id

(Optional) Displays the IS-IS traffic statistics for the specified IS-IS instance only.

The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

Command Default

No instance ID specified displays IS-IS traffic statistics for all the IS-IS instances.

IS-IS traffic statistics are displayed for all interfaces.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The show isis statistics command displays IS-IS traffic counters for the specified interface or all traffic counters if no interface is specified.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis statistics command that shows all traffic counters:


  Router#show isis statistics 
  IS-IS isp statistics:
    Fast PSNP cache (hits/tries): 164115/301454
    Fast CSNP cache (hits/tries): 41828/43302
    Fast CSNP cache updates: 2750
    LSP checksum errors received: 0
    LSP Dropped: 1441
    SNP Dropped: 1958
    UPD Max Queue size: 2431
    Average transmit times and rate:
      Hello:          0 s,     987947 ns,          4/s
      CSNP:           0 s,    1452987 ns,          0/s
      PSNP:           0 s,    1331690 ns,          0/s
      LSP:            0 s,    1530018 ns,          1/s
    Average process times and rate:
      Hello:          0 s,     874584 ns,         41/s
      CSNP:           0 s,     917925 ns,         29/s
      PSNP:           0 s,    1405458 ns,          0/s
      LSP:            0 s,    4352850 ns,          0/s
    Level-1:
      LSPs sourced (new/refresh): 3376/2754
      IPv4 Unicast
        SPF calculations           : 520
        ISPF calculations          : 0
        Next-hop Calculations      : 0
        Partial Route Calculations : 0
    Level-2:
      LSPs sourced (new/refresh): 4255/3332
      IPv4 Unicast
        SPF calculations           : 432
        ISPF calculations          : 0
        Next-hop Calculations      : 8
        Partial Route Calculations : 0
    Interface GigabitEthernet0/1/0/1.1:
    Level-1 Hellos (sent/rcvd): 22398/25633
    Level-1 DR Elections      : 66
    Level-1 LSPs (sent/rcvd)  : 246/7077
    Level-1 CSNPs (sent/rcvd) : 0/33269
    Level-1 PSNPs (sent/rcvd) : 22/0
    Level-1 LSP Flooding Duplicates  : 25129
    Level-2 Hellos (sent/rcvd): 22393/67043
    Level-2 DR Elections      : 55
    Level-2 LSPs (sent/rcvd)  : 265/437
    Level-2 CSNPs (sent/rcvd) : 0/86750
    Level-2 PSNPs (sent/rcvd) : 0/0
    Level-2 LSP Flooding Duplicates  : 78690

This table describes the significant fields shown in the display.

Table 25. show isis statistics Field Descriptions
Field	Description
Fast PSNP cache (hits/tries)	Number of successful lookups (hits) along with the number of lookup attempts (tries). To save time or processing power when receiving multiple copies of the same LSP, IS-IS attempts to look up incoming LSPs to see if they have been received recently.
Fast CSNP cache (hits/tries)	Number of successful lookups (hits) along with the number of lookup attempts (tries). To reduce CSNP construction time, IS-IS maintains a cache of CSNPs and attempts to look up CSNP in this cache before transmission on the interface.
Fast CSNP cache updates	Number of times the CSNP cache has been updated since the last clearing of statistics. The cache is updated on LSP addition or removal from the database.
LSP checksum errors received	Number of internal checksum errors received in LSPs.
IIH (LSP/SNP) dropped	Number of hello, LSP, and SNP messages dropped.
IIH (UPD) Max Queue size	Maximum number of queued packets.
Average transmit times and rate	Average time taken to transmit the pdu type across all interfaces and the corresponding rate at which the pdu type is being transmitted.
Average process times and rate	Average time taken to process an incoming pdu type across all interfaces and the corresponding rate at which the pdu type is being received.
LSPs sourced (new/refresh)	Number of LSPs this IS-IS instance has created or refreshed. To find more details on these LSPs, use the show isis lsp-log command.
SPF calculations	Number of shortest path first (SPF) calculations. SPF calculations are performed only when the topology changes. They are not performed when external routes change. The interval at which SPF calculations are performed is configured using the spf-interval command.
iSPF calculations	Number of incremental shortest path first (iSPF) calculations. iSPF calculations are performed only when ISPF has been configured in the isis address family configuration submode.
Partial Route Calculations	Number of partial route calculations (PRCs). PRCs are processor intensive. Therefore, it may be useful to limit their number, especially how often a PRC is done, especially on slower networking devices. Increasing the PRC interval reduces the processor load on the router, but might slow the rate of convergence. The interval at which PRC calculations are performed is configured using the spf-interval command.
Level-(1/2) (LSPs/CSNPs/PSNPs/Hellos) (sent/rcvd)	Number of LSPs, Complete Sequence Number Packets (CSNPs), Partial Sequence Number Packets (PSNPs), and hello packets sent or received on this interface.
PTP Hellos (sent/rcvd)	Point-to-point (PTP) hellos sent and received.
LSP Retransmissions	Total number of retransmissions on each IS-IS LSP on a point-to-point interface. The LSP retransmission interval can be configured using the retransmit-throttle-interval command.
Level-(1.2) DRElections	Total number of Designated Intermediate System elections that have taken place. These counts are maintained on an individual level basis.
LSP Flooding Duplicates	Number of duplicate LSPs filtered from flooding to the neighbor. In case of parallel interfaces to the same neighbor, IS-IS optimizes the flooding by avoiding sending the same LSP copy on other interfaces.

Related Commands


Command	Description
show isis spf-log	Displays how often and why the router has run a full SPF calculation.
spf-interval	Sets IS-IS throttling of shortest path first (SPF) calculations.

show isis topology

To display a list of connected Intermediate System-to-Intermediate System (IS-IS) routers in all areas, use the show isis topology command in EXEC mode.

show isis [instance instance-id] [ [ipv4 | ipv6 | afi-all] [unicast | multicast [topology {all | topo-name}] | safi-all]] | summary | level {1 | 2} [multicast-intact] [systemid system-id] [detail]

Syntax Description


instance `instance-id`	(Optional) Displays the IS-IS topology for the specified IS-IS instance only. The `instance-id` argument is the instance identifier (alphanumeric) defined by the router isis command.
ipv4	(Optional) Specifies IP Version 4 address prefixes.
ipv6	(Optional) Specifies IP Version 6 address prefixes.
afi-all	(Optional) Specifies all address prefixes.
unicast	(Optional) Specifies unicast address prefixes.
multicast	(Optional) Specifies multicast address prefixes.
topology `topo-name`	(Optional) Specifies topology table information and name of the topology table.
safi-all	(Optional) Specifies all secondary address prefixes.
summary	(Optional) Displays a brief list of the IS-IS topology.
level { 1 \| 2 }	(Optional) Displays the IS-IS link-state topology for Level 1 or Level 2 independently.
multicast-intact	(Optional) Displays multicast intact information on the IS-IS topology.
systemid `system-id`	(Optional) Displays the information for the specified router only.
detail	(Optional) Displays detailed information on the IS-IS topology.

Command Default

No instance ID specified displays a list of connected routers in all areas for all the IS-IS instances.

Both Level 1 and Level 2 is configured if no level is specified.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the show isis topology command to verify the presence and connectivity among all routers in all areas.

Use the show isis topology flex-algo dataplane command to display information on Flexible Algorithms.

Task ID


Task ID	Operations
isis	read

Examples

The following is sample output from the show isis topology command:


  RP/0/RSP0/CPU0:router# show isis topology
  
  IS-IS isp paths to (Level-1) routers
      System Id       Metric  Next-hop Interface       SNPA
      ensoft-5        10      ensoft-5        PO0/4/0/1       *PtoP*        
      ensoft-5        10      ensoft-5        Gi0/5/0/0       0003.6cff.0680
      ensoft-11       --
      
      IS-IS isp paths to (Level-2) routers
      System Id       Metric  Next-hop Interface       SNPA
      ensoft-5        10      ensoft-5        PO0/4/0/1       *PtoP*        
      ensoft-5        10      ensoft-5        Gi0/5/0/0       0003.6cff.0680
      ensoft-11       --

This table describes the significant fields shown in the display.

Table 26. show isis topology ipv4 unicast Field Descriptions
Field	Description
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Metric	Metric assigned to the link and used to calculate the cost from each router using the links in the network to other destinations. Range is 1 to 16777214. Default is 1 to 63 for narrow metric and 1 to 16777214 for wide metric. 0 is set internally if no metric has been specified by the user.
Next-hop	Address of the next-hop.
Interface	Interface used to reach the neighbor.
SNPA	Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.

The following is sample output from the show isis topology command with the summary keyword specified:


  RP/0/RSP0/CPU0:router# show isis topology summary
  
  IS-IS 10 IS Topology Summary IPv4 Unicast
                            L1                         L2
                  Reach  UnReach  Total      Reach  UnReach  Total
                 ------- ------- -------    ------- ------- -------
  Router nodes:        1       1       2          1       1       2
  Pseudo nodes:        0       0       0          0       0       0
  
   Total nodes:        1       1       2          1       1       2

This table describes the significant fields shown in the display.

Table 27. show isis topology summary Field Descriptions
Field	Description
L1/L2	IS-IS level of the router.
Reach	Number of router nodes or pseudonodes that are reachable.
UnReach	Number of router nodes or pseudonodes that are unreachable.
Total	Total number of reachable and unreachable nodes.

show protocols (IS-IS)

To group a number of protocol show commands according to the specified address family, use the show protocols command in EXEC mode.

show protocols [afi-all | ipv4 | ipv6] [all | protocol]

Syntax Description


afi-all	(Optional) Specifies all address families.
ipv4	(Optional) Specifies an IPv4 address family.
ipv6	(Optional) Specifies an IPv6 address family.
all	(Optional) Specifies all protocols for a given address family.
`protocol`	(Optional) Specifies a routing protocol. For the IPv4 address family, the options are: bgp isis ospf rip eigrp For the IPv6 address family, the options are: bgp isis ospfv3

Command Default

If no address family is specified, the default is IPv4.

Command Modes

EXEC

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Support for IPv6 was added

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

If IPv6 is enabled on an IS-IS instance, the instance is displayed in the show protocols ipv6 command output. IPv4 IS-IS instances are displayed in the show protocols ipv4 command output.

When using the show protocols command with the ipv6 or ipv4 keyword, you get all routing instances in that particular address family—not only IS-IS instances.

Task ID


Task ID	Operations
isis	read
rib	read

Examples

The following example shows the output for the show protocols command :


  Router# show protocols ipv4
  
  IS-IS Router: uut
    System Id: 0000.0000.12a8
    IS Levels: level-1-2
    Manual area address(es):
      49.1515.1515
    Routing for area address(es):
      49.1515.1515
    Non-stop forwarding: Disabled
    Most recent startup mode: Cold Restart
    Topologies supported by IS-IS:
      IPv4 Unicast
        Level-1
          Metric style (generate/accept): Narrow/Narrow
          ISPF Status: Disabled
        Level-2
          Metric style (generate/accept): Narrow/Narrow
          ISPF Status: Disabled
        Redistributing:
          static
        Distance: 115
      IPv6 Unicast
        Level-1
          ISPF Status: Disabled
        Level-2
          ISPF Status: Disabled
        No protocols redistributed
        Distance: 45
    Interfaces supported by IS-IS:
      GigabitEthernet 0/6/0/0 is running actively (active in configuration)

This table describes the significant fields shown in the display.

Table 28. show protocols ipv4 Field Descriptions
Field	Description
System ID	Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
IS Levels	IS-IS level of the router.
Manual area address(es)	Area addresses configured manually on the originating router.
Routing for area address(es)	Area addresses for which this router provides the routing.
Non-stop forwarding	Status and name of NSF.
Most recent startup mode	Mode in which the most recent startup was performed.
Topologies supported by IS-IS	Address and subaddress family IS-IS are configured.
Metric style	Type, length, and value (TLV) objects accepted by IS-IS. To configure this value, see the metric-style narrow, metric-style transition, or metric-style wide command.
ISPF status	State of iSPF configuration for this IS-IS instance. Four states exist: Disabled if iSPF has not been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm. Dormant if iSPF has been configured but is awaiting initial convergence before initializing. Awake if iSPF has been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm. Active if IS-IS is ready to consider using the iSPF algorithm whenever a new route calculation needs to be run.
Redistributing	IS-IS is configured to redistribute IP static routes into Level 1 or Level 2. The redistribute command is used to configure redistribution.
Distance	Administrative distance.
Interfaces supported by IS-IS	Interfaces and their states currently supported by IS-IS. Both operational and configuration status are displayed.

The following example shows how to disable the IPv4 address family, with no output shown for IS-IS IPv4 instances from the show protocols ipv4 command:


Router# configure
Router(config)# router isis uut
Router(config-isis)# no address-family ipv4 unicast
Router(config-isis)# commit

Router# show protocols ipv4

Related Commands


Command	Description
metric-style narrow	Configures the IS-IS software to generate and accept old-style type, length, and value (TLV) objects.
metric-style transition	Configures the IS-IS software to generate and accept both old-style and new-style type length, and value (TLV) objects.
metric-style wide	Configures the IS-IS software to generate and accept only new-style type, length, and value (TLV) objects.
redistribute (IS-IS)	Redistributes routes from one IS-IS instance into another instance.

shutdown (IS-IS)

To disable the Intermediate System-to-Intermediate System (IS-IS) protocol on a particular interface, use the shutdown command in interface configuration mode. To re-enable the IS-IS protocol, use the no form of this command.

shutdown

no shutdown

Command Default

IS-IS protocol is enabled.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example disables the IS-IS protocol on GigabitEthernet interface 0/1/0/1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet0/1/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# shutdown

single-topology

To configure the link topology for IP Version 4 (IPv4) when IP Version 6 (IPv6) is configured, use the single-topology command in address family configuration mode. To remove the single-topology command from the configuration file and restore the system to its default condition, use the no form of this command.

single-topology

no single-topology

Command Default

Performs in multitopology mode in which independent topologies for IPv4 and IPv6 are running in a single area or domain.

Command Modes

IPv6 address family configuration

Command History


Release	Modification
Release 3.9.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the single-topology command to allow Intermediate System-to-Intermediate System (IS-IS) for IPv6 to be configured on interfaces along with an IPv4 network protocol. All interfaces must be configured with the identical set of network protocols, and all routers in the IS-IS area (for Level 1 routing) or the domain (for Level 2 routing) must support the identical set of network layer protocols on all interfaces.

When single-topology support for IPv6 is being used, only old-style type, length, and value (TLV) objects may be used and a single shortest path (SPF) individual level is used to compute IPv4 (if configured) and IPv6 routes. The use of a single SPF means that both IPv4 IS-IS and IPv6 IS-IS routing protocols must share a network topology.

To allow link information to be shared between IPv4 and IPv6, you must configure the single-topology command for an address family. In single-topology IPv6 mode, the configured metric is always the same for both IPv4 and IPv6.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to enable single-topology mode for IPv6:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# net 49.0000.0000.0001.00
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv6 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# single-topology

snmp-server traps isis

snmp-server traps isis {all | traps set}

no snmp-server traps isis {all | traps set}

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Examples


  
            RP/0/RSP0/CPU0:router(config)# snmp-server traps isis
  
    adjacency-change                isisAdjacencyChange
    all                             Enable all IS-IS traps
    area-mismatch                   isisAreaMismatch
    attempt-to-exceed-max-sequence  isisAttemptToExceedMaxSequence
    authentication-failure          isisAuthenticationFailure
    authentication-type-failure     isisAuthenticationTypeFailure
    corrupted-lsp-detected          isisCorruptedLSPDetected
    database-overload               isisDatabaseOverload
    id-len-mismatch                 isisIDLenMismatch
    lsp-error-detected              isisLSPErrorDetected
    lsp-too-large-to-propagate      isisLSPTooLargeToPropagate
    manual-address-drops            isisManualAddressDrops
    max-area-addresses-mismatch     isisMaxAreaAddressesMismatch
    orig-lsp-buff-size-mismatch     isisOrigLSPBuffSizeMismatch
    own-lsp-purge                   isisOwnLSPPurge
    protocols-supported-mismatch    isisProtocolsSupportedMismatch
    rejected-adjacency              isisRejectedAdjacency
    sequence-number-skip            isisSequenceNumberSkip
    version-skew                    isisVersionSkew
  
  RP/0/RSP0/CPU0:router(config)#snmp-server traps isis all


            RP/0/RSP0/CPU0:router(config)# snmp-server traps isis area-mismatch lsp-error-detected

spf-interval

To customize IS-IS throttling of shortest path first (SPF) calculations, use the spf-interval command in address family configuration mode. To restore default values, use the no form of this command.

spf-interval [initial-wait initial | secondary-wait secondary | maximum-wait maximum] . . . [level {1 | 2}]

no spf-interval [ [initial-wait initial | secondary-wait secondary | maximum-wait maximum] . . . ] [level {1 | 2}]

Syntax Description


initial-wait `initial`	Initial SPF calculation delay (in milliseconds) after a topology change. Range is 0 to 120000.
secondary-wait `secondary`	Hold time between the first and second SPF calculations (in milliseconds). Range is 0 to 120000.
maximum-wait `maximum`	Maximum interval (in milliseconds) between two consecutive SPF calculations. Range is 0 to 120000.
level { 1 \| 2 }	(Optional) Enables the SPF interval configuration for Level 1 or Level 2 independently.

Command Default

initial-wait initial : 50 milliseconds

secondary-wait secondary : 200 milliseconds

maximum-wait maximum : 5000 milliseconds

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

SPF calculations are performed only when the topology changes. They are not performed when external routes change.

Use the spf-interval command to control how often the software can perform the SPF calculation. The SPF calculation is processor intensive. Therefore, it may be useful to limit how often this calculation is done, especially when the area is large and the topology changes often. Increasing the SPF interval reduces the processor load of the router, but potentially slows the rate of convergence.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to set the initial SPF calculation delay to 10 milliseconds and the maximum interval between two consecutive SPF calculations to 5000 milliseconds:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# spf-interval initial-wait 10 maximum-wait 5000

spf-interval ietf

To set an shortest path first (SPF) interval in IS-IS for SPF calculations, use the spf-interval ietf command in the System Admin Config mode. Use the no form of this command to enable the fabric bundle port.

spf-interval ietf [ initial-wait msec | short-wait msec | long-wait msec | learn-interval msec | holddown-interval msec ] [ level { 1 | 2 } ]

Syntax Description


spf-interval	Specifies the number of seconds between two consecutive SPF calculations.
ietf	Specifies Internet Engineering Task Force (IETF) RFC standard 8405.
initial-wait `msec`	Initial SPF calculation delay before running a route calculation. The initial-wait must be less than or equal to short-wait. Range is 0 to 120000. The default value is 50 milliseconds.
short-wait `msec`	Short SPF calculation delay before running a route calculation. The short-wait must be less than or equal to long-wait. Range is 0 to 120000. The default value is 200 milliseconds.
long-wait `msec`	Long SPF calculation delay before running a route calculation. Range is 0 to 120000. The default value is 5000 milliseconds.
learn-interval `msec`	Time To Learn interval for running a route calculation. The learn-interval must be less than or equal to holddown-interval. Range is 0 to 120000. The default value is 500 milliseconds.
holddown-interval `msec`	Hold-down interval for running a route calculation. Range is 0 to 120000. The default value is 10000 milliseconds.
level { 1 \| 2 }	(Optional) Enables the SPF interval configuration for Level 1 or Level 2 independently.

Command Default

None

Command Modes

System Admin Config mode

Command History


Release	Modification
Release 7.7.1	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

SPF calculations are performed only when the topology changes. They are not performed when external routes change.

Task ID


Task ID	Operations
is-is	read, write

Example

The following example shows how to configure IETF to set an SPF interval in IS-IS for SPF calculations.

Router# configure
Router(config)# router isis isp
Router(config-isis)# address-family ipv4 unicast
Router(config-isis-af)# spf-interval ietf?
initial-wait   Initial delay before running a route calculation [50]
short-wait     Short delay before running a route calculation [200]
long-wait      Long delay before running a route calculation [5000]
learn-interval Time To Learn interval for running a route calculation [500]
holddown-interval  Holddown interval for running a route calculation [10000]
level             Set SPF interval for one level only
Router(config-isis-af)# spf-interval ietf
Router(config-isis-af)#commit

The following show command displays the output with the new spf-interval algorithm. The output displays the actual delay taken to compute the SPF.

Router# show isis ipv4 spf-log last 5 detail 
   IS-IS 1 Level 2 IPv4 Unicast Route Calculation Log
                    Time Total Trig.
Timestamp    Type   (ms) Nodes Count First Trigger LSP    Triggers
------------ ----- ----- ----- ----- -------------------- -----------------------
--- Wed Mar 16 2022 ---
15:31:49.763  FSPF     1     6     3         tb5-r4.00-00 LINKBAD PREFIXBAD
  Delay:                 101ms (since first trigger)                  
                         261177ms (since end of last calculation)
  Trigger Link:          tb5-r2.00
  Trigger Prefix:        34.1.24.0/24
  New LSP Arrivals:      0
  SR uloop:              No
  Next Wait Interval:    200ms					    
  RIB Batches:           1 (0 critical, 0 high, 0 medium, 1 low)
  Timings (ms):          +--Total--+
                          Real   CPU
    SPT Calculation:         1     1
    Route Update:            0     0
                         ----- -----

spf prefix-priority (IS-IS)

To assign a priority to an ISIS prefix for customizing the RIB update sequence, use thespf prefix-priority command in address family configuration mode. To restore default values, use the no form of this command.

spf prefix-priority [level {1 | 2}] {critical | high | medium} {access-list-name | tag tag}

no spf prefix-priority [level {1 | 2}] {critical | high | medium} [access-list-name | tag tag]

Syntax Description


level { 1 \| 2 }	(Optional) Enables the assignment of a priority to Level 1 or Level 2 independently.
critical	Assigns a critical priority.
high	Assigns a high priority.
medium	Assigns a medium priority.
`access-list-name`	Name of an access list.
tag `tag`	Specifies a tag to indicate priority. The `tag` argument range is 1 to 4294967295.

Command Default

By default, IPv4 prefixes with a length of 32 and IPv6 prefixes with a length of 128 are given medium priority. The remaining prefixes are given low priority.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the spf prefix-priority command to change the sequence of prefix updates to the RIB after an SPF is run. ISIS installs prefixes in the RIB according to the following priority order:

Critical > High > Medium > Low

The spf prefix-priority command supports prefix lists for the first three priorities. The unmatched prefixes are updated with low priority.

If a spf prefix-priority is specified, the default behavior of prioritizing either length 32 or 128 prefixes for IPv4 or IPv6, respectively, as medium is disabled.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to set the prefix priorities:


  RP/0/RSP0/CPU0:router(config)# ipv4 prefix-list isis-critical-acl 
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# 10 permit 0.0.0.0/0 eq 32 
  !
  RP/0/RSP0/CPU0:router(config)# ipv4 prefix-list isis-med-acl 
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# 10 permit 0.0.0.0/0 eq 29 
  !
  RP/0/RSP0/CPU0:router(config)# ipv4 prefix-list isis-high-acl 
  RP/0/RSP0/CPU0:router(config-ipv4_pfx)# 10 permit 0.0.0.0/0 eq 30 
  !
  RP/0/RSP0/CPU0:router(config)# router isis ring 
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 unicast 
  RP/0/RSP0/CPU0:router(config-isis-af)# spf prefix-priority critical isis-critical-acl 
  RP/0/RSP0/CPU0:router(config-isis-af)# spf prefix-priority high isis-high-acl 
  RP/0/RSP0/CPU0:router(config-isis-af)# spf prefix-priority medium isis-med-acl

summary-prefix (IS-IS)

To create aggregate addresses for the Intermediate System-to-Intermediate System (IS-IS) protocol, use the summary-prefix command in address family configuration mode. To restore the default behavior, use the no form of this command.

Syntax Description


address	Summary address designated for a range of IPv4 addresses. The `address` argument must be in four-part, dotted-decimal notation.
`/` `prefix-length`	Length of the IPv4 or IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address compose the prefix (the network portion of the address). A slash must precede the decimal value.
ipv6-prefix	Summary prefix designated for a range of IPv6 prefixes. The `ipv6-prefix` argument must be in the form documented in RFC 2373, in which the address is specified in hexadecimal using 16-bit values between colons.
level { 1 \| 2 }	(Optional) Redistributes routes into Level 1 or Level 2 and summarizes them with the configured address and mask value.
tag `tag`	Sets a tag value. The value range is 1- 4294967295.

Command Default

All redistributed routes are advertised individually.

Both Level 1 and Level 2 are configured if no level is specified.

Command Modes

Address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.
Release 3.9.0	Tag keyword and IPv6 support was added.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Multiple groups of addresses can be summarized for a given level. Routes learned from other routing protocols can also be summarized. The metric used to advertise the summary is the smallest metric of all the more-specific routes. Use the summary-prefix command to help reduce the size of the routing table.

This command also reduces the size of the link-state packets (LSPs) and thus the link-state database. It also helps ensure stability, because a summary advertisement depends on many more specific routes. If one more-specific route flaps, in most cases, this flap does not cause a flap of the summary advertisement.

The drawback of summary addresses is that other routes might have less information to calculate the most optimal routing table for all individual destinations.

Note

When IS-IS advertises a summary prefix, it automatically inserts the summary prefix into the IP routing table but labels it as a “discard” route entry. Any packet that matches the entry is discarded to prevent routing loops. When IS-IS stops advertising the summary prefix, the routing table entry is removed.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to redistribute Open Shortest Path First (OSPF) routes into IS-IS:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 ipv6 unicast
  RP/0/RSP0/CPU0:router(config-isis-af)# redistribute ospf 2 level-2
  RP/0/RSP0/CPU0:router(config-isis-af)# summary-prefix 10.10.10.10 level-2 
  RP/0/RSP0/CPU0:router(config-isis-af)# summary-prefix 10.10.10.10

suppressed

To allow an IS-IS interface to participate in forming adjacencies without advertising connected prefixes in the system link-state packets (LSPs), use the suppressed command in interface configuration mode. To enable advertising connected prefixes, use the no form of this command.

suppressed

no suppressed

Command Default

Interface is active.

Command Modes

Interface configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the suppressed command to reduce the number of routes that IS-IS has to maintain, improving convergence times after an isolated failure. Improvement is noticeable if the command is used widely throughout the network. Other routers in the domain do not install routes to the affected connected prefixes.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to disable the advertisement of connected prefixes on GigabitEthernet interface 0/1/0/1:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet /1/0/1
  RP/0/RSP0/CPU0:router(config-isis-if)# suppressed

Related Commands


Command	Description
passive (IS-IS)	Suppresses S-IS packets on an interface.

tag (IS-IS)

To associate and advertise a tag with the prefix of an IS-IS interface, use the tag command in interface address family configuration mode. To restore the default behavior, use the no form of this command.

tag tag

no tag [tag]

Syntax Description


`tag`	Interface tag. Range is 1 to 4294967295.

Command Default

Default is that no tag is associated and advertised.

Command Modes

Interface address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to associate and advertise an interface tag:


  RP/0/RSP0/CPU0:router(config)# router isis isp
  RP/0/RSP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0
  RP/0/RSP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
  RP/0/RSP0/CPU0:router(config-isis-if-af)# tag 234

Related Commands


Command	Description
spf prefix-priority (IS-IS)	Assigns a priority to an ISIS prefix for customizing the RIB update sequence.

topology-id

To differentiate one topology in the domain from another while configuring a multicast routing table, use the topology-id command in Intermediate System-to-Intermediate System (IS-IS) address family configuration submode. To disable the topology use the no form of the command.

topology-id isis-multicast-topology-id-number

no topology-id isis-multicast-topology-id-number

Syntax Description


`isis-multicast-topology-id-number`	ID number for a specific IS-IS multicast topology. Range is 6 to 4095.

Command Default

No topology is associated with a routing table by default.

Command Modes

IS-IS address family configuration

Command History


Release	Modification
Release 3.7.2	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operations
isis	read, write

Examples

The following example shows how to differentiate a topology from another in the multicast routing table in IS-IS routing:


  RP/0/RSP0/CPU0:router(config)# router  isis isp
  RP/0/RSP0/CPU0:router(config-isis)# address-family ipv4 multicast topology    green  
  RP/0/RSP0/CPU0:router(config-isis-af)# topology-id  2666

Related Commands


Command	Description
address-family multicast topology (IS-IS)	Used in conjunction with the topology-id command, enables a multicast topology globally when configuring Intermediate System-to-Intermediate System (IS-IS) routing.

trace (IS-IS)

To set the the IS-IS buffer size, use the trace command in router configuration mode. To return to the default value, use the no form of this command.

trace [detailed | severe | standard] max-trace-entries

no trace [detailed | severe | standard]

Syntax Description


detailed	Specifies the buffer size for detailed traces. Range is
severe	Specifies the buffer size for severe traces. Range is
standard	Specifies the buffer size for standard traces. Range is
`max-trace-entries`	Sets the maximum number of trace entries. Range is 1-20000

Command Default

None

Command Modes

Router IS-IS configuration

Command History


Release	Modification
Release 3.9.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operation
isis	read, write

Examples

The following example shows how to set the isis buffer size for severe traces to 1200:


RP/0/RSP0/CPU0:router(config)#router isis isp
RP/0/RSP0/CPU0:router(config-isis)#trace sever 1200

ucmp (IS-IS)

To enable unequal cost multipath (UCMP) calculation for Intermediate System-to-Intermediate System (IS-IS), use the ucmp command in IS-IS address family configuration mode. To disable UCMP for IS-IS, use the no form of this command.

ucmp [ prefix-list prefix-list-name ] [ variance value ]

no ucmp

Syntax Description


prefix-list	(Optional) Specifies prefix-list name to filter UCMP paths based on prefixes.
`prefix-list-name`	Name of the prefix-list to be specified to filter UCMP paths.
variance	(Optional) Specifies variance parameter to filter UCMP paths based on cost.
`variance-value`	Variance value. The variance value is expressed in terms of percentage of the Primary path metric. Range is 101 to 10000. Default variance value is 200.

Command Default

UCMP is disabled.

Command Modes

IS-IS IPv4 address family

IS-IS IPv6 address family

Command History


Release	Modification
Release 4.3.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Enabling the ucmp command will make the router calculate UCMP nexthops for all the prefixes in the routing table.

The UCMP path calculation can be controlled such that UCMP nexthops are calculated only for a certain set of prefixes. Use the ucmp command with the prefix-set option to enable this functionality.

If there are multiple UCMP nexthops with various metrics, then the selection of the number of UCMP nexthops is controlled by the variance option in the UCMP command. The variance value is expressed in terms of percentage of the primary path metric. For example, if variance value is 150 and primary path metric is 100, then select all the UCMP nexthops with metrics from 101 to 150.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to enable calculation of UCMP nexthops for all the prefixes in the routing table:


Router#configure 
Router(config)#router isis isp
Router(config-isis)#address-family ipv6 unicast 
Router(config-isis-af)#ucmp

This example shows how to enable calculation of UCMP nexthops for a set of prefixes in the prefix-list list1 :


Router#configure 
Router(config)#router isis isp
Router(config-isis)#address-family ipv6 unicast 
Router(config-isis-af)#ucmp prefix-list list1

This example shows how to enable calcualtion of UCMP mexthops with variance value 120 :


Router#configure 
Router(config)#router isis isp
Router(config-isis)#address-family ipv6 unicast 
Router(config-isis-af)#ucmp variance 120

Related Commands


Command	Description
ucmp delay-interval	Specifies delay between primary SPF completion and start of UCMP computation.
ucmp exclude interface	Excludes an interface from unequal cost multipath (UCMP) computation.
bandwidth	Configures the bandwidth of an interface.

ucmp delay-interval

To specify delay between primary SPF completion and start of UCMP computation, use the ucmp delay-interval command in IS-IS address family configuration mode. To disable this functionality, use the no form of this command.

ucmp delay-interval delay-interval

no ucmp delay-interval

Syntax Description


`delay-interval`	Delay interval value in milliseconds. Range is 100 to 65535 milliseconds. The default value for the interval is 100 milliseconds.

Command Default

UCMP delay interval is set to 100 milliseconds.

Command Modes

IS-IS IPv4 address family

IS-IS IPv6 address family

Command History


Release	Modification
Release 4.3.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to set the delay between primary SPF completion and the start of UCMP computation, to 800 milliseconds:


Router#configure 
Router(config)#router isis isp
Router(config-isis)#address-family ipv6 unicast 
Router(config-isis-af)#ucmp delay-interval 800

Related Commands


Command	Description
ucmp is-is	Enables unequal cost multipath (UCMP) calculation for Intermediate System-to-Intermediate System (IS-IS).
ucmp exclude interface	Excludes an interface from unequal cost multipath (UCMP) computation.
bandwidth	Configures the bandwidth of an interface.

ucmp exclude interface

To exclude an interface from unequal cost multipath (UCMP) computation, use the ucmp exclude interface command in IS-IS address family configuration mode. To disable this functionality, use the no form of this command.

ucmp exclude interface type interface-path-id

no ucmp exclude interface type interface-path-id

Syntax Description

type

Interface type. For more information, use the question mark ( ? ) online help function.

interface-path-id

Physical interface or virtual interface.

Note

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

Command Default

None

Command Modes

IS-IS IPv4 address family

IS-IS IPv6 address family

Command History


Release	Modification
Release 4.3.0	This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the ucmp exclude interface command to exclude an interface from being selected as a UCMP backup path.

Task ID


Task ID	Operation
isis	read, write

Examples

This example shows how to exclude interface POS 0/3/0/1 from UCMP computation:


Router#configure 
Router(config)#router isis isp
Router(config-isis)#address-family ipv6 unicast
Router(config-isis-af)#ucmp exclude interface POS 0/3/0/1

Related Commands


Command	Description
ucmp is-is	Enables unequal cost multipath (UCMP) calculation for Intermediate System-to-Intermediate System (IS-IS).
ucmp delay-interval	Specifies delay between primary SPF completion and start of UCMP computation.
bandwidth	Configures the bandwidth of an interface.

Bias-Free Language

Results

Chapter: IS-IS Commands

IS-IS Commands

address-family (IS-IS)

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

address-family multicast topology (IS-IS)

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

Related Commands

adjacency-check disable

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

advertise passive-only

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

adjacency stagger (IS-IS)

Command Default

Command Modes

Usage Guidelines

Examples

algorithm 0

Syntax Description

Command Modes

Command History

Usage Guidelines

Task ID

attached-bit receive ignore

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

Related Commands

attached-bit send

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

Related Commands

authentication-check disable

Command Default

Command Modes

Command History

Task ID

Examples

circuit-type

Syntax Description

Command Default

Command Modes

Command History

Usage Guidelines

Task ID

Examples

Related Commands