Moving IS-IS Traffic off a Router

Problem

You are getting ready to perform router maintenance and you want to move all IS-IS traffic off the router.

Solution

Configure the router so that it appears to be overloaded with IS-IS traffic:

	[edit protocols isis]
	aviva@RouterG#  
set overload

Discussion

As you are preparing to perform maintenance on a router in a production network, you want to move traffic off that router so that network services are not interrupted during your maintenance window. The set overload command tricks the router into believing that it is overloaded and can handle any more IS-IS transit traffic, and the result is that IS-IS transit traffic is sent to other routers. IS-IS traffic destined to interfaces directly attached to the local router continues to reach the router.

To check that the IS-IS traffic has moved off the router, use show interfaces commands to verify that traffic has moved off the upstream interfaces. The detail and extensive versions of this command report traffic statistics for most interface types. If the router is part of an LSP, use the show mpls lsp transit command to verify that transit LSPs have moved off the router.