- dead-interval (OSPF virtual link)
- dead-interval (OSPFv3 virtual link)
- default-information originate (EIGRP)
- default-information originate (IS-IS)
- default-information originate (OSPF)
- default-information originate (OSPFv3)
- default-information originate (RIP)
- default isis passive-interface
- default-metric (EIGRP)
- default-metric (OSPF)
- default-metric (OSPFv3)
- default-metric (RIP)
- delay
- delay minimum
- disable-peer-as-check (BGP)
- discard-route
- distance (EIGRP)
- distance (IS-IS)
- distance (OSPF)
- distance (OSPFv3)
- distance (RIP)
- distribute
- down-bit-ignore
D Commands
This chapter describes the Cisco NX-OS unicast routing commands that begin with the letter D.
dead-interval (OSPF virtual link)
To set the interval during which at least one hello packet must be received from a neighbor on an Open Shortest Path First (OSPF) virtual link before the router declares that neighbor as down, use the dead interval command. To restore the default, use the no form of this command.
Syntax Description
Defaults
The default value for seconds is our times the interval set by the hello-interval command.
Command Modes
Command History
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Usage Guidelines
Use the dead interval command in virtual link configuration mode to configure the dead interval advertised in OSPF hello packets. This value must be the same for all networking devices on the virtual link.
You can configure a shorter dead interval ( seconds) to detect a down neighbor faster and improve convergence. A shorter dead interval may lead to virtual link instability by incorrectly declaring a slow neighbor as down.
Use the show ip ospf virtual-links command to verify the dead interval.
Examples
This example shows how to configure the OSPF dead interval to 20 seconds:
Related Commands
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Configures the Interval between hello packets that Cisco NX-OS sends on the virtual link. |
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dead-interval (OSPFv3 virtual link)
To set the interval during which at least one hello packet must be received from a neighbor on an Open Shortest Path First version 3 (OSPFv3) virtual link before the router declares that neighbor as down, use the dead interva l command. To restore the default, use the no form of this command.
Syntax Description
Defaults
The default value for seconds is our times the interval set by the hello-interval command.
Command Modes
Command History
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Usage Guidelines
Use the dead interval command in virtual link configuration mode to configure the dead interval advertised in OSPFv3 hello packets. This value must be the same for all networking devices on the virtual link.
You can configure a shorter dead interval ( seconds) to detect a down neighbor faster and improve convergence. A shorter dead interval may lead to virtual link instability by incorrectly declaring a slow neighbor as down.
Use the show ospfv3 virtual-links command to verify the dead interval.
Examples
This example shows how to configure the OSPFv3 dead interval to 20 seconds:
Related Commands
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Configures the interval between hello packets that Cisco NX-OS sends on the virtual link. |
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default-information originate (EIGRP)
To generate a default route into the Enhanced Interior Gateway Routing Protocol (EIGRP), use the default-information originate command in the appropriate configuration mode. To disable this feature, use the no form of this command.
default-information originate [ always ] [ route-map map-name ]
no default-information originate
Syntax Description
Defaults
Command Modes
Address-family configuration
Router configuration
Router VRF configuration
Command History
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Usage Guidelines
Examples
This example shows how to originate a default route (0.0.0.0/0) to all routes that pass the Condition route map.
Related Commands
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Redistributes routes from other routing protocols into EIGRP. |
default-information originate (IS-IS)
To control the origination of a default route, use the default-information originate command.
default-information originate [ always ] [ route-map name ]
Syntax Description
(Optional) Specifies the name of the routing rules route map to announce default routes. The name can be up to 63 characters. |
Defaults
The default route is not redistributed into the IS-IS routing domain.
Command Modes
Router configuration
VRF configuration
Command History
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Usage Guidelines
You can force a default route into an IS-IS routing domain. Whenever you specifically configure redistribution of routes into an IS-IS routing domain, by default, the default route is not redistributed into the IS-IS routing domain. The default-information originate route-map command generates a default route into IS-IS, which can be controlled by a route map. You can use the route map to identify the level into which the default route is to be announced, and you can specify other filtering options configurable under a route map. You can use a route map to conditionally advertise the default route, depending on the existence of another route in the routing table of the router.
Examples
This example shows how to always advertise the default route:
This example shows how to specify a route map to conditionally advertise the default route:
Related Commands
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default-information originate (OSPF)
To generate a default external route into an Open Shortest Path First (OSPF) routing domain, use the default-information originate command. To disable this feature, use the no form of this command.
default-information originate [ always ] [ route-map map-name ]
no default-information originate [ always ] [ route-map map-name ]
Syntax Description
Defaults
Advertises the default route if the route is in the route table.
Command Modes
Command History
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Usage Guidelines
Use the default-information originate command to assign a default route for redistributed routes. Whenever you use the redistribute command to redistribute routes into an OSPF routing domain, Cisco NX-OS automatically becomes an Autonomous System Boundary Router (ASBR). However, an ASBR does not, by default, generate a default route into the OSPF routing domain.
Use the route-map keyword to filter redistributed routes so that Cisco NX-OS generates a default route only for routes that pass the route map. Use the always keyword to generate the default route regardless of whether the default route is in the route table.
Note
The default-information originate command ignores match statements in the optional route map.
Examples
This example shows how to configure the default route redistributed into the OSPF routing domain for the Enhanced Interior Gateway Protocol (EIGRP):
Related Commands
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default-information originate (OSPFv3)
To generate a default external route into an Open Shortest Path First version 3 (OSPFv3) routing domain, use the default-information originate command. To disable this feature, use the no form of this command.
default-information originate [ always ] [ route-map map-name ]
no default-information originate [ always ] [ route-map map-name ]
Syntax Description
Defaults
Advertises the default route if the route is in the route table.
Command Modes
Command History
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Usage Guidelines
Use the default-information originate command to assign a default route for redistributed routes. Whenever you use the redistribute command to redistribute routes into an OSPFv3 routing domain, Cisco NX-OS automatically becomes an Autonomous System Boundary Router (ASBR). However, an ASBR does not, by default, generate a default route into the OSPFv3 routing domain.
Use the route-map keyword to filter redistributed routes so that Cisco NX-OS generates a default route only for routes that pass the route map. Use the always keyword to generate the default route regardless of whether the default route is in the route table.
Note The default-information originate command ignores match statements in the optional route map.
Examples
This example shows how to configure the default route redistributed into the OSPFv3 routing domain for the Border Gateway Protocol (BGP):
Related Commands
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default-information originate (RIP)
To generate a default route into the Routing Information Protocol (RIP), use the default-information originate command in router address-family configuration mode. To disable this feature, use the no form of this command.
default-information originate [ always ] [ route-map map-name ]
no default-information originate
Syntax Description
Defaults
Command Modes
Router address-family configuration
Command History
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Usage Guidelines
Examples
This example shows how to originate a default route (0.0.0.0/0) to all routes that pass the Condition route map:
Related Commands
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default isis passive-interface
To allow all Intermediate System-to-Intermediate System (IS-IS) interfaces to be set as passive by default, use the default isis passive-interface command.
default isis passive-interface {level-1 | level-1-2 | level-2}
Syntax Description
Defaults
Command Modes
Command History
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Usage Guidelines
Examples
This example shows how to allow all IS-IS interfaces to be set as passive by default:
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Re-enables sending of routing updates on an IS-IS interface and activates only those interfaces that need adjacencies. |
default-metric (EIGRP)
To set metrics for an Enhanced Interior Gateway Routing Protocol (EIGRP), use the default-metric command. To remove the metric value and restore the default state, use the no form of this command.
default-metric bandwidth delay reliability loading mtu
Syntax Description
Defaults
bandwidth: 100000
delay: 100 (tens of microseconds)
reliability: 255
loading: 1
MTU: 1500
Command Modes
Address-family configuration
Router configuration
Router VRF configuration
Command History
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Usage Guidelines
Use the default-metric command with the redistribute command to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever external metrics do not convert to EIGRP metrics, you can use a default metric to provide a reasonable substitute to the external metric and enable the redistribution to proceed.
Examples
This example shows how to take redistributed Routing Information Protocol (RIP) metrics and translate them into EIGRP metrics with the following values: bandwidth = 1000, delay = 100, reliability = 250, loading = 100, and MTU = 1500.
Related Commands
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Redistributes routes from one routing domain into another routing domain. |
default-metric (OSPF)
To set default metric values for the Open Shortest Path First (OSPF) routing protocol, use the default-metric command. To return to the default state, use the no form of this command.
no default-metric metric-value
Syntax Description
Default metric value appropriate for the specified routing protocol. The range is from 1 to 1677214. |
Defaults
The metric for redistributed, connected, and static routes is set to 25.
Command Modes
Command History
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Usage Guidelines
Use the default-metric command with the redistribute command to configure the same metric value for all redistributed routes except static and directly connected routes. A default metric helps to redistribute routes with incompatible metrics. Whenever external route metrics do not convert to an OSPF metric, use a default metric to enable the redistribution to proceed.
Note The default-metric command does not apply to the redistribution of directly connected routes into OSPF. Use a route map to change the default metric for directly connected routes.
Examples
This example shows how to configure OSPF to redistribute RIP and BGP and set the default metric to 10:
Related Commands
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default-metric (OSPFv3)
To set default metric values for the Open Shortest Path First version 3 (OSPFv3) routing protocol, use the default-metric command. To return to the default state, use the no form of this command.
no default-metric metric-value
Syntax Description
Default metric value appropriate for the specified routing protocol. The range is from 1 to 1677214. |
Defaults
The metric for redistributed, connected, and static routes is set to 25.
Command Modes
Command History
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Usage Guidelines
Use the default-metric command with the redistribute command to configure the same metric value for all redistributed routes except directly connected routes. A default metric helps to redistribute routes with incompatible metrics. Whenever external route metrics do not convert to an OSPFv3 metric, use a default metric to enable the redistribution to proceed.
Note The default-metric command does not apply to the redistribution of directly connected routes into OSPF. Use a route map to change the default metric for directly connected routes.
Examples
This example shows how to configure OSPFv3 to redistribute RIP and BGP and set the default metric to 10:
Related Commands
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Redistributes routes from another routing domain into OSPFv3. |
default-metric (RIP)
To set default metric values for the Routing Information Protocol (RIP), use the default-metric command in router address-family configuration mode. To return to the default state, use the no form of this command.
Syntax Description
Defaults
Command Modes
Router address-family configuration
Command History
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Usage Guidelines
Use the default-metric command with the redistribute command to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever external metrics do not convert to RIP metrics, you can use a default metric to provide a reasonable substitute to the external metric and enable the redistribution to proceed.
Examples
This example shows how to advertise Open Shortest Path First (OSPF) routes using RIP and assign the OSPF-derived routes with a RIP metric of 10:
Related Commands
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Generates a default route for routes redistributed into RIP. |
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Redistributes routes from one routing domain into another routing domain. |
delay
To delay a state change for Object Tracking, use the delay command. To disable this function, use the no form of this command.
delay { up up-time [ down down-time] | down down-time [ up up-time ]}
Syntax Description
Delays the object track state change for an up condition. The range is from 0 to 180 seconds. |
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Delays the object track state change for a down condition. The range is from 0 to 180 seconds. |
Defaults
Command Modes
Command History
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Usage Guidelines
Use the delay command to delay when object tracking detects an up or down state change for a tracked object or track list. This delay helps prevent state flapping.
Examples
This example shows how to configure the delay timer for a tracked object:
switch(config)# track 1 interface ethernet 1/2 line-protocol
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delay minimum
To delay Hot Standby Router Protocol (HSRP) initialization after a reload or after an interface comes up, use the delay minimum command. To disable this function, use the no form of this command.
delay minimum [ min-delay ] reload [reload-delay ]
no delay minimum [ min-delay ] reload [reload-delay ]
Syntax Description
Defaults
Command Modes
Command History
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Usage Guidelines
Use delay minimum command to delay HSRP initialization either after a reload or after an interface comes up. This configuration allows the interface and router to stabilize after the interface comes up and helps prevent HSRP state flapping.
Examples
This example shows how to configure a minimum delay of 3 seconds, and a group initialization delay of 10 seconds:
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disable-peer-as-check (BGP)
To disable checking the peer autonomous system number (ASN) during route advertisement, use the disable-peer-as-check command.
Syntax Description
Defaults
Command Modes
config-router-vrf-neighbor-af mode
Command History
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Usage Guidelines
Examples
This example shows how to disable checking the peer ASN during a route advertisement:
switch(config)# feature-set mpls
switch(config)# feature mpls l3vpn
switch(config)# router bgp 1.1
switch(config-router)# neighbor 33.0.1.63 remote-as 100
config-router-vrf-neighbor)# address-family ipv4 unicast
switch(config-router-neighbor-af)# neighbor 33.0.1.63 remote-as 100
switch(config-router-vrf-neighbor)# address-family ipv4 unicast
switch(config-router-vrf-neighbor-af)# disable-peer-as-check
switch(config-router-vrf-af)#
Related Commands
discard-route
For Cisco NX-OS to automatically configure a discard route for the summary address to prevent routing black holes and route loops, use the discard-route command. To prevent the discard routes from being created, use the no form of this command.
discard-route { internal | external }
no discard-route { internal | external }
Syntax Description
Defaults
Command Modes
Command History
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Usage Guidelines
Examples
This example shows how to automatically configure a discard route for the summary address to prevent routing black holes and route loops:
This example shows how to prevent the discard routes from being created:
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Configures an Open Shortest Path First (OSPF) routing instance. |
distance (EIGRP)
To allow the use of two administrative distances—internal and external—for the Enhanced Interior Gateway Routing Protocol (EIGRP) that could provide a better route to a node, use the distance command. To reset to default, use the no form of this command.
distance internal-distance external-distance
Syntax Description
Defaults
Command Modes
Address-family configuration
Router configuration
Router VRF configuration
Command History
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Usage Guidelines
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is an integer from 0 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 and should be ignored.
Use the distance command if another protocol is known to provide a better route to a node than was actually learned through the external EIGRP or some internal routes should be preferred by EIGRP.
Examples
This example shows how to set the administrative distance of all EIGRP 1 internal routes to 80 and all EIGRP external routes to 130:
Related Commands
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Displays information about the Enhanced Interior Gateway Routing Protocol (EIGRP) running on the router. |
distance (IS-IS)
To define an administrative distance for routes that are inserted into the routing table, use the distance configuration mode command. To return the administrative distance to its default distance definition, use the no form of this command.
Syntax Description
Defaults
The default route is not redistributed into the IS-IS routing domain.
Command Modes
Router configuration
VRF configuration
Command History
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Usage Guidelines
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is an integer from 0 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
Examples
This example shows how to set the administrative distance to 90:
Related Commands
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Specifies the Network Entity Title (NET) for an IS-IS process. |
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distance (OSPF)
To define the Open Shortest Path First (OSPF) route administrative distance, use the distance command. To restore the default, use the no form of this command.
Syntax Description
Administrative distance for all routes local to this OSPF process. The range is from 1 to 255. |
Defaults
Command Modes
Command History
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Usage Guidelines
Use the distance command to set a distance for an entire group of routes. Use the distance command when you configure multiple routing protocols, and you want to choose one set of routes over the other.
Examples
This example shows how to set the distance to 200, making the route less reliable:
distance (OSPFv3)
To define the Open Shortest Path First version 3 (osPFv3) route administrative distance, use the distance command. To restore the default, use the no form of this command.
Syntax Description
Administrative distance for all routes local to this OSPFv3 process. The range is from 1 to 255. |
Defaults
Command Modes
Command History
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Usage Guidelines
Use the distance command to set a distance for an entire group of routes. Use the distance command when you configure multiple routing protocols, and you want to choose one set of routes over the other.
Examples
This example shows how to set the distance to 200, making the route less reliable:
distance (RIP)
To define the administrative distance assigned to routes discovered by the Routing Information Protocol (RIP), use the distance command in the router address-family configuration mode. To remove the distance and restore the system to its default condition, use the no form of this command.
Syntax Description
Administrative distance to be assigned to RIP routes. The range is from 0 to 255. |
Defaults
Command Modes
Router address-family configuration
Command History
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Usage Guidelines
Use the distance command to change the preference of RIP routes over other protocol routes. Numerically, an administrative distance is an integer from 0 to 255. In general, a higher value indicates a lower trust rating. An administrative distance of 255 means that the routing information source cannot be trusted at all and should be ignored.
Table 4-1 lists default administrative distances.
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Examples
This example shows how to set the administrative distance for RIP:
Related Commands
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distribute
To distribute routes between specific IS-IS levels, use the distribute command. To return to the default setting, use the no form of this command.
distribute { level-1 | level-2 } into { level-1 | level-2 } { all | route-map name }
Syntax Description
Defaults
The default route is not distributed into the IS-S routing domain. If enabled, IS-IS allows distribution of route between level-1 and level-2 such that optimal inter-area routing could be obtained.
Command Modes
Router configuration
VRF configuration
Command History
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Usage Guidelines
level-1 summarizes the IP address into the level-1 area. Only routes redistributed into Level 1 are summarized with the configured address and mask value.
level-2 summarizes the IP address into the level-2 area. Routes learned by level-1 routing are summarized into the level-2 backbone with the configured address and mask value. Redistributed routes into level-2 IS-IS will be summarized also.
In IS-IS, all areas are stub areas, which means that no routing information is leaked from the backbone (level-2) into areas (level-1). Level-1-only routers use default routing to the closest level-1-level-2 router in their area. This command enables you to redistribute level-2 IP routes into level-1 areas. This redistribution enables level-1-only routers to pick the best path for an IP prefix to get out of the area. This is an IP-only feature, CLNS routing is still stub routing.
For more control and scalability, a distribute list or a route map can control which level-2 IP routes can be redistributed into level-1. This command allows large IS-IS-IP networks to use areas for better scalability.
Examples
This example distributes level-1 routes into a level-2 network:
down-bit-ignore
To disable down bit (DN bit) checking on a provider edge (PE) router, use the down-bit-ignore command in OSPF VRF configuration mode. To return to the default setting, use the no form of this command.
Syntax Description
Defaults
By default, the down bit (DN bit) checking is enabled. The information from the link-state advertisement (LSA) for which the DN bit is set is ignored during Open Shortest Path First (OSPF) route calculation.
Command Modes
Command History
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Usage Guidelines
This command is supported only in the OSPF VRF mode on a PE router. This command is not supported in OSPF VRF mode on a non-PE router.
When a PE receives a type 3, 5, or 7 LSA with the DN bit set from a customer edge (CE) router, the information from the LSA is not used during OSPF route calculation. The DN bit ignore feature enables a PE router to process type-3, type-5, and type-7 LSAs that are received from a CE router when the DN bit is set. When you configure the DN bit ignore feature, the PE router includes these LSAs in OSPF route computation.
The DN bit is used to prevent routing loops in Layer 3 virtual private network (VPN) configurations using OSPF in a PE-CE scenario. The DN bit ignore feature is applicable for only certain topologies, such as a hub and spoke topology of PE routers with multiple virtual routing and forwarding (VRF) CEs connected to the hub PE. You should be use this command with caution because it can cause routing loops.
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