Configuring VPLS Fast Reroute Priority
When a path is rerouted after a link failure by using the MPLS
fast reroute feature, the router repairs the affected next hops by
switching them from the active label switched path (LSP) to the standby
LSP. To specify the order in which the router repairs next hops and
restores traffic convergence 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.
The router repairs next hops and restores known unicast, unknown unicast, broadcast, and multicast traffic for VPLS routing instances in the following order, based on the fast reroute priority configuration:
The router repairs next hops for high-priority VPLS routing instances.
The router repairs next hops for medium-priority VPLS routing instances.
The router repairs next hops for low-priority VPLS routing instances.
Because the router repairs next hops for VPLS routing instances
configured with high fast reroute priority 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), the router follows no particular
order for traffic restoration of VPLS routing instances.
VPLS fast reroute priority is not supported on EX Series switches.
To configure high, medium, or low fast reroute priority for a VPLS routing instance, include the fast-reroute-priority statement:
fast-reroute-priority (high | medium | low);
You can include this statement at the following hierarchy levels:
[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.
The following example snippet shows configuration of high fast reroute priority for a VPLS routing instance named test-vpls:
test-vpls {
instance-type vpls;
forwarding-options {
fast-reroute-priority high;
}
}
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 CLI Explorer.