Cisco IOS IP Routing: RIP Command Reference

Routing Information Protocol Commands

auto-summary (RIP)

To restore the default behavior of automatic summarization of subnet routes into network-level routes, use the auto-summary command in router configuration mode. To disable this function and send subprefix routing information across classful network boundaries, use the no form of this command.

auto-summary

no auto-summary

Syntax Description

This command has no arguments or keywords.

Command Default

Enabled (the software summarizes subprefixes to the classful network boundary when crossing classful network boundaries).

Command Modes

Router configuration

Command History

Usage Guidelines

Route summarization reduces the amount of routing information in the routing tables.

RIP Version 1 always uses automatic summarization. If you are using RIP Version 2, you can turn off automatic summarization by specifying the no auto-summary command. Disable automatic summarization if you must perform routing between disconnected subnets. When automatic summarization is off, subnets are advertised.

Examples

In the following example, network numbers are not summarized automatically:

router rip

 version 2

 no auto-summary

bfd all-interfaces

To enable Bidirectional Forwarding Detection (BFD) for all interfaces participating in the routing process, use the bfd all-interfaces command in router configuration or address-family interface configuration mode. To disable BFD for all neighbors on a single interface, use the no form of this command.

bfd all-interfaces

no bfd all-interfaces

Syntax Description

This command has no arguments or keywords.

Command Default

BFD is disabled on the interfaces participating in the routing process.

Command Modes

Router configuration (config-router) and address-family interface configuration (config-router-af)

Command History

Usage Guidelines

There are two methods to configure routing protocols to use BFD for failure detection. To enable BFD for all interfaces, enter the bfd all-interfaces command in router configuration mode. In Cisco IOS Release 12.4(24)T, Cisco IOS 12.2(33)SRA and earlier releases, the bfd all-interfaces command works in router configuration mode and address-family interface mode.

In Cisco IOS Release 15.0(1)M and later releases, the bfd all-interfaces command in named router configuration mode is replaced by the bfd command in address-family interface configuration mode. Use the bfd command in address-family interface configuration mode to achieve the same functionality as that of the bfd all interfaces command in router configuration mode.

Examples

The following example shows how to enable BFD for all Enhanced Interior Gateway Routing Protocol (EIGRP) neighbors:

Router> enable

Router# configure terminal

Router(config)# router eigrp 123

Router(config-router)# bfd all-interfaces

Router(config-router)# end

The following example shows how to enable BFD for all Intermediate System-to-Intermediate System (IS-IS) neighbors:

Router> enable

Router# configure terminal

Router(config)# router isis tag1

Router(config-router)# bfd all-interfaces

Router(config-router)# end

The following example shows how to enable BFD for all Open Shortest Path First (OSPF) neighbors:

Router> enable

Router# configure terminal

Router(config)# router ospf 123

Router(config-router)# bfd all-interfaces

Router(config-router)# end

The following example shows how to enable BFD for all EIGRP neighbors, using the bfd command in address-family interface configuration mode:

Router> enable

Router# configure terminal

Router(config)# router eigrp my_eigrp

Router(config-router)# address-family ipv4 autonomous-system 100 

Router(config-router-af)# af-interface FastEthernet 0/0

Router(config-router-af-interface)# bfd

The following example shows how to enable BFD for all Routing Information Protocol (RIP) neighbors:

Router> enable

Router# configure terminal

Router(config)# router rip

Router(config-router)# bfd all-interfaces

Router(config-router)# end

Related Commands

default-information originate (RIP)

To generate a default route into Routing Information Protocol (RIP), use the default-information originate command in router configuration mode. To disable this feature, use the no form of this command.

default-information originate [on-passive | route-map map-name]

no default-information originate

Syntax Description

Command Default

No default routes are generated into RIP.

Command Modes

Router configuration (config-router)

Command History

Usage Guidelines

The route map referenced in the default-information originate command cannot use an extended access list; it can use a standard access list.

When you configure the default-information originate on-passive command, RIP sends the default route on a passive interface. A default route is the network route with which a router communicates when no other known route exists for a given IP packet's destination address. Before a RIP provider edge (PE) router can send the default route to the customer edge (CE) router, you must configure the interfaces facing the CE as passive interfaces by using the default-information originate on-passive command.

Once you configure the default-information originate on-passive command, the output of the show ip protocols command displays that RIP default routes are sent on passive interfaces.

Applying a condition to determine when the default route is originated is called conditional default origination.

Examples

The following example shows how to originate a default route (0.0.0.0/0) over a certain interface when 172.17.0.0/16 is present. In this example a route map condition is applied.

router rip 

 version 2

 network 172.17.16.0

 default-information originate route-map condition

!

 route-map condition permit 10

 match ip address 10

 set interface s1/0

!

access-list 10 permit 172.17.16.0 0.0.0.255

!

Related Commands

default-metric (RIP)

To set default metric values for Routing Information Protocol (RIP), use the default-metric command in router configuration mode. To return to the default state, use the no form of this command.

default-metric number-value

no default-metric [number-value]

Syntax Description

Defaults

Built-in, automatic metric translations, as appropriate for each routing protocol

Command Modes

Router configuration

Command History

Usage Guidelines

The default-metric command is used in conjunction with the redistribute router configuration command to cause the current routing protocol to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever metrics do not convert, using a default metric provides a reasonable substitute and enables the redistribution to proceed.

Examples

The following example shows a router in autonomous system 109 using both the RIP and the Open Shortest Path First (OSPF) routing protocols. The example advertises OSPF-derived routes using RIP and assigns the OSPF-derived routes a RIP metric of 10.

router rip

 default-metric 10

 redistribute ospf 109

Related Commands

flash-update-threshold

To suppress regularly scheduled flash updates, use the flash-update-threshold command in router configuration mode. To return to the default state, use the no form of this command.

flash-update-threshold seconds

no flash-update-threshold

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Usage Guidelines

This command suppresses flash updates when the arrival of a regularly scheduled update matches the number of seconds that is configured with the seconds argument. The range of seconds that can be configure is from 0 to 30 seconds. If the number of seconds matches the number of seconds or is less than the number seconds that is configured with the seconds argument, the flash update is suppressed. If the numbers seconds until the flash update arrives exceeds the number of seconds that is configured with the seconds argument, the flash update is not suppressed. The regular scheduled interval for flash updates and the configuration of the suppression of flash updates can be verified with the show ip protocol command.

Examples

The following example configures a router to suppress a regularly scheduled flash update if the update is due in 10 seconds or less:

router rip

 flash-update-threshold 10 

Related Commands

input-queue

The input-queue command defines the number of received, but not yet processed RIP update packets contained in the Routing Information Protocol (RIP) input queue. Use the input-queue command in router configuration mode. To remove the configured depth and restore the default depth, use the no form of this command.

input-queue depth

no input-queue

Syntax Description

Defaults

A depth of 50.

Command Modes

Router configuration

Command History

Usage Guidelines

Consider using the input-queue command if you have a high-end router that is sending at high speed to a low-speed router that might not be able to receive at the high speed. Configuring this command will help prevent the routing table from losing information.

Another way to prevent the routing table from losing information is to use the output-delay command to change the interpacket delay for RIP updates.

Examples

The following example sets the depth of the RIP input queue to 100:

router rip

 input-queue 100

Related Commands

ip rip authentication key-chain

To enable authentication for Routing Information Protocol (RIP) Version 2 packets and to specify the set of keys that can be used on an interface, use the ip rip authentication key-chain command in interface configuration mode. To prevent authentication, use the no form of this command.

ip rip authentication key-chain name-of-chain

no ip rip authentication key-chain [name-of-chain]

Syntax Description

Defaults

No authentication is provided for RIP packets.

Command Modes

Interface configuration

Command History

Usage Guidelines

If no key chain is configured with the key-chain command, no authentication is performed on the interface (not even the default authentication).

Examples

The following example configures the interface to accept and send any key belonging to the key chain named trees:

ip rip authentication key-chain trees

Related Commands

ip rip authentication mode

To specify the type of authentication used in Routing Information Protocol (RIP) Version 2 packets, use the ip rip authentication mode command in interface configuration mode. To restore clear text authentication, use the no form of this command.

ip rip authentication mode {text | md5}

no ip rip authentication mode

Syntax Description

Defaults

Clear text authentication is provided for RIP packets.

Command Modes

Interface configuration

Command History

Usage Guidelines

RIP Version 1 does not support authentication.

Examples

The following example configures the interface to use MD5 authentication:

ip rip authentication mode md5

Related Commands

ip rip initial-delay

To delay the initiation of RIPv2 neighbor sessions using MD5 authentication until the network connectivity between the neighbor routers is fully operational, use the ip rip initial-delay command in interface, or subinterface configuration mode. To remove the configured delay, use the no form of this command.

ip rip initial-delay delay

no ip rip initial-delay

Syntax Description

Command Default

The delay of RIPv2 neighbor sessions is not configured.

Command Modes

Interface configuration (config-if)
Subinterface configuration (config-subif)

Command History

Usage Guidelines

Some non-Cisco routers will not allow an MD5-authenticated RIPv2 neighbor session to start when the sequence number of the first MD5 packet received from the Cisco router is greater than 0. The IP-RIP Delay Start feature is used on Cisco routers to delay the initiation of RIPv2 neighbor sessions using MD5 authentication until the network connectivity between the neighbor routers is fully operational. This ensures the sequence number of the first MD5 packet that the router sends to the non-Cisco neighbor router is 0.

Examples

The following example configures the router to wait 45 seconds before sending the first MD5 authentication packet to a non-Cisco device:

Router(config)# interface POS 0/1/0

Router(config-subif)# ip rip initial-delay 45

Related Commands

ip rip receive version

To specify a Routing Information Protocol (RIP) version to receive on an interface basis, use the ip rip receive version command in interface configuration mode. To follow the global version rules, use the no form of this command.

ip rip receive version [1] [2]

no ip rip receive version

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Interface configuration

Command History

Usage Guidelines

Use this command to override the default behavior of RIP as specified by the version command. This command applies only to the interface being configured. You can configure the interface to accept both RIP versions.

Examples

The following example configures the interface to receive both RIP Version 1 and Version 2 packets:

ip rip receive version 1 2

The following example configures the interface to receive only RIP Version 1 packets:

ip rip receive version 1

Related Commands

ip rip send version

To specify a Routing Information Protocol (RIP) version to send on an interface basis, use the ip rip send version command in interface configuration mode. To follow the global version rules, use the no form of this command.

ip rip send version [1] [2]

no ip rip send version

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Interface configuration

Command History

Usage Guidelines

Use this command to override the default behavior of RIP as specified by the version command. This command applies only to the interface being configured.

Examples

The following example configures the interface to send both RIP Version 1 and Version 2 packets out the interface:

ip rip send version 1 2

The following example configures the interface to send only RIP Version 2 packets out the interface:

ip rip send version 2

Related Commands

ip rip triggered

To enable triggered extensions to Routing Information Protocol (RIP), use the ip rip triggered command in interface configuration mode. To disable triggered extensions to RIP, use the no form of this command.

ip rip triggered

no ip rip triggered

Syntax Description

This command has no arguments or keywords.

Defaults

This command is disabled by default.

Command Modes

Interface configuration

Command History

Usage Guidelines

When triggered extensions to RIP are enabled, routing updates are sent on the WAN only if one of the following events occurs:

•The router receives a specific request for a routing update. (Full database is sent.)

•Information from another interface modifies the routing database. (Only latest changes are sent.)

•The interface comes up or goes down. (Partial database is sent.)

•The router is first powered on, to ensure that at least one update is sent. (Full database is sent.)

You might want to enable this feature if you are using an on-demand circuit and you are charged for usage time. Fewer routing updates will incur lower usage costs.

Entries in the routing database can be either temporary or semipermanent. Entries learned from broadcasts on LANs are temporary; they will expire if not periodically refreshed by more broadcasts.

Entries learned from a triggered response on the WAN are semipermanent; they do not time out like other entries. Certain events can cause these routes to time out, such as the interface going down, or if the outgoing interface is the same as the incoming interface. Neighbor updates of the routes with a metric of 16 (infinity) mean the route is unreachable, and those routes are eventually removed from the routing table.

Examples

The following example enables triggered extensions to RIP:

interface serial 0

 ip rip triggered

Related Commands

ip rip v2-broadcast

To allow Routing Information Protocol (RIP) Version 2 update packets to be sent as broadcast packets instead of multicast packets, use the ip rip v2-broadcast command in interface configuration mode. To disable the broadcast of IP RIP Version 2 update packets that are sent as broadcast packets, use the no form of this command.

ip rip v2-broadcast

no ip rip v2-broadcast

Syntax Description

This command has no arguments or keywords.

Command Default

This command is disabled by default. Unless the ip rip v2-broadcast commend is entered, RIP Version 2 update packets are sent as multicast packets.

Command Modes

Interface configuration (config-if)

Command History

Usage Guidelines

Use the ip rip v2-broadcast command to broadcast RIP Version 2 broadcast updates to hosts that do not listen to multicast broadcasts. Version 2 updates (requests and responses) will be sent to the IP broadcast address 255.255.255.255 instead of the IP multicast address 224.0.0.9.

In order to reduce unnecessary load on those hosts that are not listening to RIP Version 2 broadcasts, the system uses an IP multicast address for periodic broadcasts. The IP multicast address is 224.0.0.9.

Note It is not necessary to configure Internet Group Management Protocol (IGMP) because the periodic broadcasts are interrouter messages that are not forwarded.

Examples

The following example configures Version 2 IP broadcast updates on RIP Ethernet interface 3/1:

Router(config) interface ethernet3/1

Router(config-if) ip address 172.16.1.1 255.255.255.0

Router(config-if) ip rip v2-broadcast

.

.

.

Router(config-if) router rip

Router(config-if) version 2

Router(config-if) network 172.0.0.0

Enter debug ip rip command to verify that RIP Version 2 IP broadcast updates are being sent to the IP broadcast address 255.255.255 instead of IP multicast address 224.0.0.9:

Router# debug ip rip

14:41:59: RIP: sending v2 update to 255.255.255.255 via Ethernet3/1 (172.16.1.1)

If the ip rip v2-broadcast command has not been entered, the output from the debug ip rip command verifies that the RIP Version 2 IP broadcast updates are being sent to the IP multicast address 224.0.0.9:

Router# debug ip rip

15:45:16: RIP: sending v2 update to 224.0.0.9 via Ethernet3.1 (172.16.1.1)

Related Commands

ip split-horizon (RIP)

To enable the split horizon mechanism, use the ip split-horizon command in interface configuration mode. To disable the split horizon mechanism, use the no form of this command.

ip split-horizon

no ip split-horizon

Syntax Description

This command has no arguments or keywords.

Defaults

Default behavior varies with media type.

Command Modes

Interface configuration

Command History

Usage Guidelines

For all interfaces except those for which either Frame Relay or Switched Multimegabit Data Service (SMDS) encapsulation is enabled, the default condition for this command is ip split-horizon; in other words, the split horizon feature is active. If the interface configuration includes either the encapsulation frame-relay or encapsulation smds command, then the default is for split horizon to be disabled. Split horizon is not disabled by default for interfaces using any of the X.25 encapsulations.

Note For networks that include links over X.25 packet switched networks (PSNs), the neighbor router configuration command can be used to defeat the split horizon feature. You can as an alternative explicitly specify the no ip split-horizon command in your configuration. However, if you do so you must similarly disable split horizon for all routers in any relevant multicast groups on that network.

Note If split horizon has been disabled on an interface and you want to enable it, use the ip split-horizon command to restore the split horizon mechanism.

Note In general, changing the state of the default for the ip split-horizon command is not recommended, unless you are certain that your application requires a change in order to properly advertise routes. If split horizon is disabled on a serial interface (and that interface is attached to a PSN), you must disable split horizon for all routers and access servers in any relevant multicast groups on that network.

Examples

The following simple example disables split horizon on a serial link. The serial link is connected to an X.25 network.

interface serial 0

 encapsulation x25

 no ip split-horizon

Related Commands

ip summary-address rip

To configure a summary aggregate address under an interface for the Routing Information Protocol (RIP), use the ip summary-address rip command in interface configuration mode. To disable summarization of the specified address or subnet, use the no form of this command.

ip summary-address rip ip-address ip-network-mask

no ip summary-address rip ip-address ip-network-mask

Syntax Description

Command Default

RIP automatically summarizes to classful network boundaries.

Command Modes

Interface configuration

Command History

Usage Guidelines

The ip summary-address rip command is used to summarize an address or subnet under a specific interface. RIP automatically summarizes to classful network boundaries. Only one summary address can be configured for each classful subnet.

Examples

In the following example the major network is 10.0.0.0. The summary address 10.2.0.0 overrides the autosummary address of 10.0.0.0, so that 10.2.0.0 is advertised out Ethernet interface 1 and 10.0.0.0 is not advertised.

Note If split horizon is enabled, neither autosummary nor interface summary addresses (those configured with the ip summary-address rip command) are advertised.

interface Ethernet1

 ip address 10.1.1.1 255.255.255.0

 ip summary-address rip 10.2.0.0 255.255.0 

 exit

router rip

 network 10.0.0.0

 end

Related Commands

neighbor (RIP)

To define a neighboring router for exchanging routing information, use the neighbor command in router configuration mode. To remove a neighboring router entry, use the no form of this command.

neighbor ip-address [bfd]

no neighbor ip-address [bfd]

Syntax Description

Command Default

No neighboring routers are defined.

Command Modes

Router configuration (config-router)

Command History

Usage Guidelines

This command permits point-to-point (nonbroadcast) exchange of routing information. When it is used in combination with the passive-interface command, routing information can be exchanged between a subset of routers and access servers on a LAN.

Use multiple neighbor commands to specify additional neighbors or peers.

Examples

In the following example, RIP updates are sent to all interfaces on network 10.108.0.0 except Ethernet interface 1. However, in this case, a neighbor router configuration command is included. This command permits the sending of routing updates to specific neighbors. One copy of the routing update is generated per neighbor.

Router> enable

Router# configure terminal

Router(config)# router rip

Router(config-router)# network 10.108.0.0

Router(config-router)# passive-interface Ethernet 1

Router(config-router)# neighbor 10.108.20.4

Router(config-router)# end

The following example shows how to enable BFD for RIP neighbors:

Router> enable

Router# configure terminal

Router(config)# neighbor 10.0.0.1 bfd

Router(config-router)# end

Related Commands

network (RIP)

To specify a list of networks for the Routing Information Protocol (RIP) routing process, use the network command in router configuration mode. To remove an entry, use the no form of this command.

network ip-address

no network ip-address

Syntax Description

Defaults

No networks are specified.

Command Modes

Router configuration

Command History

Usage Guidelines

The network number specified must not contain any subnet information. There is no limit to the number of network commands you can use on the router. RIP routing updates will be sent and received only through interfaces on this network.

RIP sends updates to the interfaces in the specified networks. Also, if the network of an interface is not specified, the interface will not be advertised in any RIP update.

Examples

The following example defines RIP as the routing protocol to be used on all interfaces connected to networks 10.99.0.0 and 192.168.7.0:

router rip

 network 10.99.0.0

 network 192.168.7.0

Related Commands

offset-list (RIP)

To add an offset to incoming and outgoing metrics to routes learned via Routing Information Protocol (RIP), use the offset-list command in router configuration mode. To remove an offset list, use the no form of this command.

offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

no offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Usage Guidelines

The offset value is added to the routing metric. An offset list with an interface type and interface number is considered extended and takes precedence over an offset list that is not extended. Therefore, if an entry passes the extended offset list and the normal offset list, the offset of the extended offset list is added to the metric.

Examples

In the following example, the router applies an offset of 10 to the delay component of a router only to access list 21:

offset-list 21 out 10

In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0:

offset-list 21 in 10 ethernet 0

output-delay

To change the interpacket delay for Routing Information Protocol (RIP) updates sent, use the output-delay command in router configuration mode. To remove the delay, use the no form of this command.

output-delay delay

no output-delay

Syntax Description

Command Default

The default interpacket delay is 0 milliseconds.

Command Modes

Router configuration

Command History

Usage Guidelines

Consider using this command if you have a high-end router that is sending at high speed to a low-speed router that might not be able to receive at the high speed. Configuring this command will help prevent the routing table from losing information.

Examples

The following example sets the interpacket delay to 10 milliseconds:

router rip

 output-delay 10

router rip

To configure the Routing Information Protocol (RIP) routing process, use the router rip command in global configuration mode. To turn off the RIP routing process, use the no form of this command.

router rip

no router rip

Syntax Description

This command has no arguments or keywords.

Command Default

No RIP routing process is defined.

Command Modes

Global configuration

Command History

Examples

The following example shows how to begin the RIP routing process:

router rip

Related Commands

service-module ip rip relay

To enable the delivery of RIP update messages from a Cisco IOS router containing an integrated cable modem or a cable modem HWIC to a Hybrid Fiber-Coaxial (HFC) CMTS when they are on different subnets, use the service-module ip rip relay command in interface configuration mode. To disable RIP relay, use the no form of this command.

service-module ip rip relay

no service-module ip rip relay

Syntax Description

This command has no keywords or arguments.

Command Default

RIP relay is disabled.

Command Modes

Interface configuration (config-if)

Command History

Usage Guidelines

The service-module ip rip relay command is used to enable the HFC RIP Relay feature that allows the delivery of RIP messages from a Cisco IOS router containing an integrated cable modem or a cable modem High-Speed WAN Interface Card (HWIC) to the Cable Modem Termination system (CMTS) when they are on different subnets. In Cisco IOS releases prior to 12.4(15)XY and 12.4(20)T, RIP messages were rejected by the CMTS because the interface on the Cisco IOS router was in a different subnet from the CMTS.

Examples

The following example enables RIP relay on an Integrated Services Router (ISR) cable modem. A static IP address is configured for the cable modem interface, and RIP relay is enabled on the interface. To allow RIP updates from unknown sources, the normal validation of the source IP address of incoming RIP routing updates is disabled. RIP is defined as the routing protocol to be used on all interfaces that are connected to networks 10.0.0.0 and 172.18.0.0.

interface Cable-Modem0/3/0

 ip address 10.5.5.5 255.255.255.0

 service-module ip rip relay

 exit 

router rip

 version 2

 no validate-update-source            

 network 10.0.0.0

 network 172.18.0.0

Related Commands

show ip rip database

To display summary address entries in the Routing Information Protocol (RIP) routing database entries if relevant are routes being summarized based upon a summary address, use the show ip rip database command in privileged EXEC mode.

show ip rip database [ip-address mask]

Syntax Description

Command Default

No default behavior or values.

Command Modes

Privileged EXEC

Command History

Usage Guidelines

Summary address entries will appear in the database only if relevant child routes are being summarized. When the last child route for a summary address becomes invalid, the summary address is also removed from the routing table.

The RIP private database is populated only if triggered extensions to RIP are enabled with the ip rip triggered command.

Examples

The following output shows a summary address entry for route 10.11.0.0/16, with three child routes active:

Router# show ip rip database

 10.0.0.0/8    auto-summary

 10.11.11.0/24    directly connected, Ethernet2

 10.1.0.0/8    auto-summary

 10.11.0.0/16    int-summary

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^

 10.11.10.0/24    directly connected, Ethernet3

 10.11.11.0/24    directly connected, Ethernet4

 10.11.12.0/24    directly connected, Ethernet5

The following is sample output from the show ip rip database command with a prefix and mask:

Router# show ip rip database 172.19.86.0 255.255.255.0

172.19.86.0/24

    [1] via 172.19.67.38, 00:00:25, Serial0

    [2] via 172.19.70.36, 00:00:14, Serial1 

Table 8 describes the fields in the display.

Related Commands

show ip rip neighbors

To display Routing Information Protocol (RIP) neighbors for which Bidirectional Forwarding Detection (BFD) sessions are created, use the show ip rip neighbors command in privileged EXEC mode.

show ip rip neighbors

Syntax Description

This command has no argument or keywords.

Command Modes

Privileged EXEC (#)

Command History

Usage Guidelines

Use the show ip rip neighbors command to display RIP neighbors for which BFD sessions are created.

Examples

The following is sample output from the show ip rip neighbors command:

Router# show ip rip neighbors

BFD sessions created for the RIP neighbors

Neighbor      Interface      SessionHandle

10.10.10.2    Ethernet0/0    1

10.10.20.2    Ethernet1/0    2

Table 9 describes the significant fields shown in the display.

Related Commands

skeptical interval

To configure cautious Cisco nonstop forwarding (NSF) helper functionality with a neighbor with an interval, use the skeptical interval command in router configuration mode. To configure a cautious NSF helper with the default interval, use the no form of this command.

skeptical interval minutes

no skeptical interval

Syntax Description

Command Default

The default interval for configuring an NSF helper is 5 minutes.

Command Modes

Router configuration (config-router)

Command History

Usage Guidelines

When the skeptical interval command is configured with an interval, NSF will not be supported with the neighbor during this period. If you configure the skeptical interval 0 command, it means that you always support NSF with the neighbor. Whenever you configure the skeptical interval command, you should also configure the nsf interval command.

Examples

The following example configures the skeptical interval to 30 minutes:

Router(config)# router isis

Router(config-router)# skeptical interval 30

Related Commands

throttle (router configuration)

To enable throttle for Routing Information Protocol (RIP) requests, use the throttle command in router configuration mode. To disable the configuration, use the no form of this command.

throttle

no throttle

Syntax Description

This command has no arguments or keywords.

Command Default

Throttle is not enabled by default.

Command Modes

Router configuration (config-router)

Command History

Usage Guidelines

You can use the throttle command if you are using RIP as a routing protocol to serve a large number of routers. This command prevents RIP from generating update packets in response to RIP requests from a faulty neighbor. Because only one RIP request per minute will be serviced from a neighbor, incoming regular updates are less likely to be dropped.

You can configure the throttle command only when the interpacket delay is configured using the output-delay command.

Examples

The following example shows how to enable throttle for RIP requests:

Router# configure terminal

Router(config-router)# network 192.0.2.1

Router(config-router)# output-delay 20

Router(config-router)# throttle

Related Commands

timers basic (RIP)

To adjust Routing Information Protocol (RIP) network timers, use the timers basic command in router configuration mode. To restore the default timers, use the no form of this command.

timers basic update invalid holddown flush

no timers basic

Syntax Description

Command Default

No RIP network timers are adjusted.

Command Modes

Router configuration

Command History

Usage Guidelines

The basic timing parameters for RIP are adjustable. Because RIP is executing a distributed, asynchronous routing algorithm, these timers must be the same for all routers and access servers in the network.

Note The current and default timer values can be seen by inspecting the output of the show ip protocols EXEC command. The relationships of the various timers should be preserved as described previously.

In addition, an address family can have explicitly specified timers that apply to that address-family (or VRF) only. The timers basic command must be specified for an address family or the system defaults for the timers basic command are used regardless of what is configured for RIP routing. The VRF does not inherit the timer values from the base RIP configuration. The VRF will always use the system default timers unless explicitly changed using the timers basic command.

Examples

The following example sets updates to be broadcast every 5 seconds. If a router is not heard from in 15 seconds, the route is declared unusable. Further information is suppressed for an additional 15 seconds. At the end of the suppression period, the route is flushed from the routing table.

router rip

 timers basic 5  15  15  30 

Note By setting a short update period, you run the risk of congesting slow-speed serial lines. A short update period can be a concern on faster-speed Ethernets and T1-rate serial lines. Also, if you have many routes in your updates, you can cause the routers to spend an excessive amount of time processing updates.

The following example show adjusting address family timers.

router rip

 version 2

 timers basic 5 10 15 20

 redistribute connected

 network 5.0.0.0

 default-metric 10

  no auto-summary

  !

  address-family ipv4 vrf foo

  timers basic 10 20 20 20

  redistribute connected

  network 10.0.0.0

  default-metric 5

  no auto-summary

  version 2

  exit-address-family

  !

  address-family ipv4 vrf bar

  timers basic 20 40 60 80

  redistribute connected

  network 20.0.0.0

  default-metric 2

  no auto-summary

  version 2

  exit-address-family

 !

validate-update-source

To have the Cisco IOS software validate the source IP address of incoming routing updates for Routing Information Protocol (RIP) and Interior Gateway Routing Protocol (IGRP) routing protocols, use the validate-update-source command in router configuration mode. To disable this function, use the no form of this command.

validate-update-source

no validate-update-source

Syntax Description

This command has no arguments or keywords.

Defaults

The behavior of this command is enabled by default.

Command Modes

Router configuration

Command History

Usage Guidelines

This command is applicable only to RIP and IGRP. The software ensures that the source IP address of incoming routing updates is on the same IP network as one of the addresses defined for the receiving interface.

Disabling split horizon on the incoming interface will also cause the system to perform this validation check.

For unnumbered IP interfaces (interfaces configured as IP unnumbered), no checking is performed.

Examples

The following example configures a router not to perform validation checks on the source IP address of incoming RIP updates:

router rip

 network 10.105.0.0

 no validate-update-source

version

To specify a Routing Information Protocol (RIP) version used globally by the router, use the version command in router configuration mode. To restore the default value, use the no form of this command.

version {1 | 2}

no version

Syntax Description

Command Default

The software receives RIP Version 1 and Version 2 packets, but sends only Version 1 packets.

Command Modes

Router configuration

Command History

Usage Guidelines

To specify RIP versions used on an interface basis, use the ip rip receive version and ip rip send version commands.

Examples

The following example enables the software to send and receive RIP Version 2 packets:

version 2

Related Commands