Configuring Rules for Selecting Equal-Cost IPv6 IS-IS Routes

If multiple equal-cost IS-IS routes are available on a network, configure the equal-cost IS-IS routes to load-balance traffic to increase the bandwidth usage of each link, or configure priorities for the equal-cost IS-IS routes to facilitate traffic management.

Context

If there are multiple IPv6 IS-IS routes with the same cost, configure load balancing for equal-cost IPv6 IS-IS routes.

Load balancing increases the link bandwidth usage and prevents network congestion caused by link overload. However, Load balancing may complicate traffic management because traffic will be randomly forwarded.

Procedure

Run system-view
The system view is displayed.
Run isis [ process-id ]
The IS-IS view is displayed.
Run ipv6 maximum load-balancing number
The maximum number of equal-cost IPv6 IS-IS routes for load balancing is set.
If the actual equal-cost routes outnumber the value specified in the ipv6 maximum load-balancing command, routes are selected for load balancing based on the following rules:
1. Route preference: Routes with lower preference value (higher preference) are selected for load balancing.
2. Next hop System ID: If routes have the same priorities, routes with smaller System ID are selected for load balancing.
3. Interface index: If routes have the same priorities and System ID, routes with lower interface index values are selected for load balancing.
Run commit
The configuration is committed.