Deployment Guide

NOTE: When using the IS-IS routing protocol to exchange IPv6 routing information and to determine destination reachability, you
can route IPv6 along with IPv4 while using a single intra-domain routing protocol. The conguration commands allow you to
enable and disable IPv6 routing and to congure or remove IPv6 prexes on links.
Except where identied, the commands described in this chapter apply to both IPv4 and IPv6 versions of IS-IS.
Conguration Tasks for IS-IS
The following describes the conguration tasks for IS-IS.
• Enabling IS-IS
• Conguring Multi-Topology IS-IS (MT IS-IS)
• Conguring IS-IS Graceful Restart
• Changing LSP Attributes
• Conguring the IS-IS Metric Style
• Conguring the IS-IS Cost
• Changing the IS-Type
• Controlling Routing Updates
• Conguring Authentication Passwords
• Setting the Overload Bit
• Debugging IS-IS
Enabling IS-IS
By default, IS-IS is not enabled.
The system supports one instance of IS-IS. To enable IS-IS globally, create an IS-IS routing process and assign a NET address. To exchange
protocol information with neighbors, enable IS-IS on an interface, instead of on a network as with other routing protocols.
In IS-IS, neighbors form adjacencies only when they are same IS type. For example, a Level 1 router never forms an adjacency with a Level 2
router. A Level 1-2 router forms Level 1 adjacencies with a neighboring Level 1 router and forms Level 2 adjacencies with a neighboring Level
2 router.
NOTE
: Even though you enable IS-IS globally, enable the IS-IS process on an interface for the IS-IS process to exchange
protocol information and form adjacencies.
To congure IS-IS globally, use the following commands.
1 Create an IS-IS routing process.
CONFIGURATION mode
router isis [tag]
tag: (optional) identies the name of the IS-IS process.
2 Congure an IS-IS network entity title (NET) for a routing process.
ROUTER ISIS mode
net network-entity-title
Specify the area address and system ID for an IS-IS routing process. The last byte must be 00.
For more information about conguring a NET, refer to IS-IS Addressing.
3 Enter the interface conguration mode.
CONFIGURATION mode
interface interface
Intermediate System to Intermediate System
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