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

IS-IS static neighbors

Updated: June 9, 2026

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Explains IS-IS static neighbor functionality and guides users through configuration steps to establish static neighbor relationships for improved topology management.

A IS-IS static neighbor is a network management feature that

  • allows the advertisement of an IS-IS link without forming an actual IS-IS adjacency

  • provides necessary link topology for controllers where IS-IS is not active, and

  • ensures the advertised link is identical to regular IS-IS links.

Table 1. Feature History Table

Feature Name

Release Information

Feature Description

IS-IS static neighbor

 Release 25.4.1

Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only*)

*This feature is supported on the Cisco 8011-32Y8L2H2FH routers.

IS-IS static neighbor

 Release 25.2.1

Introduced in this release on: Fixed Systems (8200 [ASIC: Q200, P100], 8700 [ASIC: P100, K100], 8010 [ASIC: A100]);Centralized Systems (8600 [ASIC: Q200]); Modular Systems (8800 [LC ASIC: Q100, Q200, P100])

IS-IS static neighbor allows the advertisement of an IS-IS link without forming an actual IS-IS adjacency. This feature is useful when a link is required in the topology for the controller, but IS-IS is not actively running on the link.

This feature introduces these changes:

CLI:

router isis static-neighbor

Additional notes

IS-IS static neighbor enables network controllers to recognize a link in the topology even if IS-IS is not actively running on that link. This feature is especially useful when a controller requires awareness of the link, but no regular IS-IS adjacency is formed.

When IS-IS static neighbor is configured, protocol operation on the interface stops, which prevents the formation of dynamic adjacencies. However, local IP subnets continue to be advertised alongside static neighbors, depending on the configuration. Use the parameters (system-id, remote address, affinity, and log advertisement changes) to define the neighbors accurately.

Usage Guidelines

Static IS-IS links are advertised when these conditions are met:

  • IS-IS interface is up, including IP/IPv6 protocols and Connectionless Network Service (CLNS) routing IO

  • static IS-IS is configured, and

  • point-to-point (p2p) IS-IS is configured.

Configure an IS-IS static neighbor

Establish an IS-IS static neighbor relationship to control adjacency parameters and advertisement policies on a router.

Before you begin

Collect these details:

  • IS-IS System-id of the static neighbor

  • Remote IPv4 or IPv6 addresses

  • Affinity link to advertise

  • Determine if you need to enable logging for static neighbor advertisement changes

Procedure

1.

Configure the IS-IS routing process, and select the interface where you want to configure the static neighbor.

Example:

Router# configure
Router(config)# router isis 1
Router(config-isis)# interface GigabitEthernet0/2/0/7
2.

Enter the static-neighbor sub-mode, and specify the static neighbor properties.

Example:

Router(config-isis-if)# static-neighbor

  • Set the system-id of the static neighbor.

    Router(config-isis-static-nbr)# system-id 0001.0002.0007

  • Specify the remote IPv4 address.

    Router(config-isis-static-nbr)# remote ipv4 address 10.2.2.2

  • (Optional) Specify the affinity link.

    Router(config-isis-static-nbr)# affinity RED

  • (Optional) Enable logging for advertisement changes.

    Router(config-isis-static-nbr)# log-advertisement-changes
3.

Use the show isis static-neighbor command to verify the IS-IS static neighbor’s operational status.

Example:

Router# show isis static-neighbor IS-IS 1

IS-IS 1 static neighbors:
System Id          Interface        State
0001.0002.0007     Gi0/2/0/3        Up
Remote IPv4 Address: 2.2.2.2
Remote IPv6 Address: 7::2
Affinity: RED
[additional status details and syslog messages]
4.

Use the show isis interface command to display IS-IS interface information, including adjacency formation and protocol state.

Example:

Router# show isis interface Gi0/2/0/3

Gi0/2/0/3             Enabled
Adjacency Formation:      Disabled (Passive due to static neighbor configuration)
Prefix Advertisement: Enabled
Protocol State: Up
Forwarding Address(es): Unknown (Intf passive due to static neighbor configuration)
[other interface and topology details]
// ...snip...