Routing Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

PDF

Routing Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Deploy and monitor RIB

Updated: June 30, 2026

Want to summarize with AI?

Explains how to use RIB show commands to verify route state, inspect route views, troubleshoot connectivity between RIB and its clients, and monitor routing behavior across the network.

RIB is not configured separately for the Cisco IOS XR system. RIB computes router connectivity to other nodes in the network based on input from the routing protocols.

You can use RIB to monitor and troubleshoot the connections between RIB and its clients. You can also use RIB monitoring to check routing connectivity between nodes in a network.

To deploy and monitor RIB, you must understand the following concepts:

Verify RIB configuration using the routing table

Use this task to verify RIB operation from the routing table output.

Use the show route commands to check summary and detailed information for the IPv4 or IPv6 unicast routing table.

Before you begin

Ensure that you have EXEC access on the router.
Ensure that RIB and the routing protocols are configured on the router.

Procedure

	1.	Display the route summary for the routing table. Example: `Router# show route summary` This command displays route summary information for the specified routing table. The default table that is summarized is the IPv4 unicast routing table.
	2.	Display detailed route information for the routing table. Example: `Router# show route ipv4 unicast` This command displays detailed route information for the specified routing table. You can enter the command with an IP address or other optional filters to limit the output. If you enter the command without filters, it displays all routes from the default IPv4 unicast routing table, which can produce extensive output depending on the network configuration.

You can confirm that RIB is running on the route processor and that the routing table contains the expected summary and detailed route information.

Troubleshoot networking and routing problems

Use this task to verify route operation between nodes and investigate routing-table behavior in RIB.

The show route command family displays active, backup, connected, local, longer-prefix, best-local, and next-hop route information.

Procedure

	1.	Display the current routes in RIB. Example: `Router# show route ipv4 unicast 192.168.1.11/8`
	2.	Display the backup routes in RIB. Example: `Router# show route ipv4 unicast backup 192.168.1.11/8`
	3.	Display the best local address for return traffic from a destination. Example: `Router# show route ipv4 unicast best-local 192.168.1.11/8` This command displays the best-local address to use for return packets from the specified destination.
	4.	Display the connected routes in the routing table. Example: `Router# show route ipv4 unicast connected` This command displays the current connected routes in the routing table.
	5.	Display the local routes in the routing table. Example: `Router# show route ipv4 unicast local` This command displays local routes for receive entries in the routing table.
	6.	Display the routes in RIB that share a given prefix. Example: `Router# show route ipv4 unicast longer-prefixes 192.168.1.11/8` This command displays the current routes in RIB that share a given number of bits with a specified network.
	7.	Display the next-hop gateway or host for a destination address. Example: `Router# show route ipv4 unicast next-hop 192.168.1.34`

You can review active, backup, local, connected, longer-prefix, and next-hop route information to troubleshoot networking and routing problems.

Disable RIB next-hop dampening

Use this task to disable RIB next-hop dampening.

You can disable next-hop dampening for the IPv4 or IPv6 address family in RIB configuration mode.

Procedure

Enter RIB configuration mode.

Example:

Router# configure
Router(config)# router rib

Disable next-hop dampening for the IPv4 or IPv6 address family.

Disable next-hop dampening for the IPv4 address family.

Example:

Router(config-rib)# address-family ipv4 next-hop dampening disable
Router(config-rib)# commit

Disable next-hop dampening for the IPv6 address family.

Example:

Router(config-rib)# address-family ipv6 next-hop dampening disable
Router(config-rib)# commit

RIB next-hop dampening is disabled for the selected address family.

RIB monitoring examples

Use these show route command examples to monitor RIB routing connectivity and troubleshoot interactions between RIB and its clients.

Output of show route command: Example

This example shows sample output from the show route command when it is entered without an address.

Router# show route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, su - IS-IS summary null, * - candidate default
       U - per-user static route, o - ODR, L - local

Gateway of last resort is 172.23.54.1 to network 0.0.0.0

C    10.2.210.0/24 is directly connected, 1d21h, HundredGigE 0/1/0/0
L    10.2.210.221/32 is directly connected, 1d21h, HundredGigE 0/1/0/0
C    10.6.100.0/24 is directly connected, 1d21h, Loopback1
L    10.6.200.21/32 is directly connected, 1d21h, Loopback0
S    192.168.40.0/24 [1/0] via 172.20.16.6, 1d21h

Output of show route backup command: Example

This example shows sample output from the show route backup command.

Router# show route backup

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
         D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
         N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
         E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
         i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2
         ia - IS-IS inter area, su - IS-IS summary null, * - candidate default
         U - per-user static route, o - ODR, L - local
  S    172.73.51.0/24 is directly connected, 2d20h, FourHundredGigE 0/0/0/1
                   Backup  O E2 [110/1] via 10.12.12.2, FourHundredGigE 0/0/0/2

Output of show route best-local command: Example

This example shows sample output from the show route best-local 10.12.12.1 command.

Router# show route best-local 10.12.12.1
  
  Routing entry for 10.12.12.1/32
    Known via "local", distance 0, metric 0 (connected)
    Routing Descriptor Blocks
      10.12.12.1 directly connected, via FourHundredGigE 0/0/0/0
        Route metric is 0

Output of show route connected command: Example

This example shows sample output from the show route connected command.

Router# show route connected
   
  C    10.2.210.0/24 is directly connected, 1d21h, HundredGigE 0/1/0/0
  C    10.6.100.0/24 is directly connected, 1d21h, Loopback1

Output of show route local command: Example

This example shows sample output from the show route local command.

Router# show route local
   
  L    10.10.10.1/32 is directly connected, 00:14:36, Loopback0
  L    10.91.36.98/32 is directly connected, 00:14:32, HundredGigE 0/1/0/0
  L    172.22.12.1/32 is directly connected, 00:13:35, FourHundredGigE 0/1/0/0
  L    192.168.20.2/32 is directly connected, 00:13:27, FourHundredGigE 0/0/0/0
  L    10.254.254.1/32 is directly connected, 00:13:26, FourHundredGigE 0/1/0/0

Output of show route ipv4 longer-prefixes command: Example

This example shows sample output from the show route ipv4 longer-prefixes command.

Router# show route ipv4 longer-prefixes 172.16.0.0/8
   
  Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
         O - OSPF, IA - OSPF inter area, N1 - OSPF NSSA external type 1
         N2 - OSPF NSSA external type 2, E1 - OSPF external type 1
         E2 - OSPF external type 2, E - EGP, i - ISIS, L1 - IS-IS level-1
         L2 - IS-IS level-2, ia - IS-IS inter area
         su - IS-IS summary null, * - candidate default
         U - per-user static route, o - ODR, L - local
  
  Gateway of last resort is 172.23.54.1 to network 0.0.0.0
  S    172.16.2.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.3.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.4.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.5.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.6.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.7.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.8.0/32 is directly connected, 00:00:24, Loopback0
  S    172.16.9.0/32 is directly connected, 00:00:24, Loopback0

Output of show route resolving-next-hop command: Example

This example shows sample output from the show route resolving-next-hop command.

Router# show route resolving-next-hop 10.0.0.1
   
Nexthop matches 10.0.0.1/31
  Known via "connected", distance 0, metric 0 (connected)
  Installed Oct 21 10:11:22.460 for 00:03:02
  Directly connected nexthops
    directly connected, via FourHundredGigE0/0/0/0
      Route metric is 0

Need help?

Open a support case

(Requires a Cisco Service Contract)

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.