The frr-policy route command filters IS-IS backup routes before the routes are added to the IP routing table.
The undo frr-policy route command cancels the filtering function.
By default, the filtering function is disabled.
| Parameter | Description | Value |
|---|---|---|
| route-policy route-policy-name |
Specifies the name of a route policy to filter IS-IS backup routes. |
The name is a string of 1 to 200 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string. |
| route-filter route-filter-name |
Specifies the name of route filter policy to filter IS-IS backup routes. |
The value is a string of 1 to 200 case-sensitive characters, spaces not supported. If parameters are included in the referenced route-filter, specify values for them in the format of (var1, var2, ...var8) behind the route-filter name. A maximum of eight parameters can be specified, and each value ranges from 1 to 200 characters. |
Usage Scenario
With the development of networks, Voice over Internet Protocol (VoIP) and on-line video services require high-quality real-time transmission. Nevertheless, if an IS-IS fault occurs, multiple processes, including fault detection, LSP update, LSP flooding, route calculation, and FIB entry delivery, must be performed to switch the traffic to a new link. As a result, it takes much more than 50 ms to rectify the fault, unable to meet the requirement for real-time services.
The frr-policy route command can be configured as required. In this case, the IS-IS backup route matching specified rules can be added to the IP routing table and delivered to the forwarding table. When a fault occurs on the route, the system can fast switch the forwarded traffic to the IS-IS backup route to protect the traffic. You can use IP prefix lists or ACLs to filter the IS-IS backup routes.Prerequisites
An IS-IS instance has been created, and fast reroute has been enabled.