Cisco NCS 5500 Series Configuration Manuals page 18

Configure Single Topology for IS-IS
Before you begin
Note To enable the router to run in single-topology mode, configure each of the IS-IS interfaces with all of the
address families enabled and "single-topology" in the address-family IPv6 unicast in the IS-IS router stanza.
You can use either the IPv6 address family or both IPv4 and IPv6 address families, but your configuration
must represent the set of all active address families on the router. Additionally, explicitly enable single-topology
operation by configuring it in the IPv6 router address family submode.
Two exceptions to these instructions exist:
1. If the address-family stanza in the IS-IS process contains the adjacency-check disable command, then
an interface is not required to have the address family enabled.
2. The single-topology command is not valid in the ipv4 address-family submode.
The default metric style for single topology is narrow metrics. However, you can use either wide metrics or
narrow metrics. How to configure them depends on how single topology is configured. If both IPv4 and IPv6
are enabled and single topology is configured, the metric style is configured in the address-family ipv4 stanza.
You may configure the metric style in the address-family ipv6 stanza, but it is ignored in this case. If only
IPv6 is enabled and single topology is configured, then the metric style is configured in the address-family
ipv6 stanza.
SUMMARY STEPS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12. address-family { ipv4 | ipv6 } [ unicast ]
13. commit
14. show isis [ instance instance-id ] interface [ type interface-path-id ] [ detail ] [ level { 1 | 2 }]
15. show isis [ instance instance-id ] topology [ systemid system-id ] [ level { 1 | 2 }] [ summary
Routing Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.3.x
6
configure
interface type interface-path-id
Do one of the following:
• ipv4 address address mask
• ipv6 address ipv6-prefix / prefix-length [ eui-64 ]
• ipv6 address ipv6-address { / prefix-length | link-local }
• ipv6 enable
exit
router isis instance-id
net network-entity-title
address-family ipv6 [ unicast ]
single-topology
exit
interface type interface-path-id
circuit-type { level-1 | level-1-2 | level-2-only }
]
Implementing IS-IS