Cisco ASR 9000 Series Routing Configuration Manual page 386

Configuring 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. configure
2. interface type interface-path-id
3. Do one of the following:
4. exit
5. router isis instance-id
6. net network-entity-title
7. address-family ipv6 [ unicast ]
8. single-topology
9. exit
10. interface type interface-path-id
11. circuit-type { level-1 | level-1-2 | level-2-only }
12. address-family { ipv4 | ipv6 } [ unicast | multicast ]
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 ]
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
356
• ipv4 address address mask
• ipv6 address ipv6-prefix / prefix-length [ eui-64 ]
• ipv6 address ipv6-address { / prefix-length | link-local }
• ipv6 enable
Implementing IS-IS