Configuring Single Topology For Is-Is - Cisco NCS 6000 Series Configuration Manual

Configuring Single Topology for IS-IS

Command or Action
Step 5
commit
Step 6 show isis [ instance instance-id ] protocol
Example:
RP/0/RP0/CPU0:router# show isis protocol
Configuring Single Topology for IS-IS
After an IS-IS instance is enabled, it must be configured to compute routes for a specific network topology.
This task explains how to configure the operation of the IS-IS protocol on an interface for an IPv4 or IPv6
topology.
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.
Routing Configuration Guide for Cisco NCS 6000 Series Routers, IOS XR Release 6.4.x
214
Purpose
• The level-2-only keyword configures the software to
perform Level 2 (backbone) routing only, and the
router establishes only Level 2 adjacencies, either with
other Level 2-only routers or with level-1-2 routers.
• The level-1-2 keyword configures the software to
perform both Level 1 and Level 2 routing. Both
Level 1 and Level 2 adjacencies are established. The
router acts as a border router between the Level 2
backbone and its Level 1 area.
(Optional) Displays summary information about the IS-IS
instance.
Implementing IS-IS