IS-IS Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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IS-IS Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Configure a global multicast topology and associate it with network interfaces

Updated: June 9, 2026

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Provides procedural instructions for configuring a global IS-IS topology and associating it with network interfaces to enable effective topology management and integration.

Set up a global topology in the default VRF, associate it with network interfaces, and control routing table attributes.

Use this procedure to configure multicast topologies as part of the IS-IS workflow on Cisco IOS XR routers. Associating a topology with interfaces ensures routes are correctly added to the routing table.

Before you begin

  • Ensure you have access to global configuration mode on your router.

  • Identify the topology name to use.

  • Know which interfaces you intend to assign to the topology.

Procedure

1.

Define the multicast topology and (optionally) set a prefix limit.

Example:


Router(config)# address-family ipv4 multicast topology green
Router(config-af)# maximum prefix 100

This sets up a topology named "green" in the default VRF and limits it to 100 prefixes.
2.

Associate one or more interfaces with the topology and enable it.

For each interface you want to assign, enter interface configuration mode and enable the topology.

Example:

Router(config-af)# interface GigabitEthernet 0/3/0/0
   Router(config-if)# address-family ipv4 multicast topology green
   Router(config-af)# interface GigabitEthernet 0/3/2/0
   Router(config-if)# address-family ipv4 multicast topology purple

This associates "GigabitEthernet 0/3/0/0" with the "green" topology and "GigabitEthernet 0/3/2/0" with the "purple" topology. Repeat these two commands for each interface and topology combination you require.