Configuring VPLS Fast Reroute Priority
When a path is rerouted after a link failure by using the MPLS fast reroute feature, the affected next hops are repaired by switching them from the active label switched path (LSP) to the standby LSP. To specify the order in which the next hops are repaired and traffic convergence is restored for VPLS routing instances after a fast reroute event, you can use the fast-reroute-priority statement to configure high, medium, or low fast reroute priority for a VPLS routing instance. By default, the fast reroute priority for a VPLS routing instance is low.
Next hops are repaired and known unicast, unknown unicast, broadcast, and multicast traffic for VPLS routing instances are restored in the following order, based on the fast reroute priority configuration:
- Next hops for high-priority VPLS routing instances are repaired.
- Next hops for medium-priority VPLS routing instances are repaired.
- Next hops for low-priority VPLS routing instances are repaired.
Because next hops for VPLS routing instances configured with high fast reroute priority are repaired first, the traffic traversing high-priority VPLS instances is restored faster than the traffic for VPLS instances configured with medium or low fast reroute priority. The ability to prioritize specific VPLS routing instances for faster convergence and traffic restoration enables service providers to offer differentiated service levels to their customers.
Within a particular fast reroute priority level (high, medium, or low), no particular order for traffic restoration of VPLS routing instances is followed.
 | Note: VPLS fast reroute priority is not supported on J Series routers. |
To configure high, medium, or low fast reroute priority for a VPLS routing instance, include the fast-reroute-priority statement:
You can include this statement at the following hierarchy levels:
- [edit forwarding-options]
- [edit logical-systems logical-system-name routing-instances routing-instance-name forwarding-options]
- [edit routing-instances routing-instance-name forwarding-options]
You can configure fast reroute priority only for routing instances with the instance-type set to vpls. If you attempt to configure fast reroute priority for a routing instance with an instance-type other than vpls, the router displays a warning message and the configuration fails.
| Note: In the VPLS documentation, the word router in terms such as PE router is used to refer to any device that provides routing functions. |
The following example snippet shows configuration of high fast reroute priority for a VPLS routing instance named test-vpls:
To display the fast reroute priority setting configured for a VPLS routing instance, use the show route instance detail operational command. For information about using this command, see the Junos OS Operational Mode Commands.
