Configuring Convergence Priorities for IS-IS Routes

If some IS-IS routes need to be converged by preference to minimize adverse impacts on services, configure those routes to have the highest convergence priority.

Context

By default, the convergence priority of 32-bit host routes is medium, and the convergence priority of the other IS-IS routes is low.

The FW allows you to configure the highest convergence priority for specific IS-IS routes so that those IS-IS routes will be converged first when a network topology changes.

Procedure

Access the system view.
system-view
Access the IS-IS process view.
isis [ process-id ]
Set convergence priorities for IS-IS routes.
prefix-priority [ level-1 | level-2 ] { critical | high | medium } { ip-prefix prefix-name | tag tag-value }

The application rules of the convergence priorities for IS-IS routes are as follows:
- Existing IS-IS routes are converged based on the priorities configured in the prefix-priority command.
- New IS-IS routes are converged based on the priorities configured in the prefix-priority command.
- If an IS-IS route conforms to the matching rules of multiple convergence priorities, the highest convergence priority is used.
- The convergence priority of a Level-1 IS-IS route is higher than that of a Level-2 IS-IS route.
- If the route level is not specified, the configuration of the prefix-priority command takes effect for both Level-1 and Level-2 IS-IS routes.
The prefix-priority command is only applicable to the public network.

After the prefix-priority command is run, the convergence priority of 32-bit host routes is low, and the convergence priorities of the other routes are determined as specified in the prefix-priority command.
Return to the system view.
quit
(Optional) Set the preference-based scheduling ratio of IPv4 routes.
ip route prefix-priority-scheduler critical-weight high-weight medium-weight low-weight

By default, the preference-based scheduling ratio of IPv4 routes is 8:4:2:1.