mpls l2vpn redundancy

Usage Scenario

After configuring the primary and secondary PWs on a PE, you can specify the PW redundancy mode. The following PW redundancy modes are supported:

FRR mode: The FRR mode is the default PW redundancy mode and does not need to be configured.

Master/slave or independent mode: is configured using the mpls l2vpn redundancy command.

• Master/slave mode: The primary and secondary PWs are manually specified on the master device, and then the local device notifies the remote device of information about the primary and secondary PWs. The master/slave PW redundancy mode works with the bypass PW to isolate network-side link faults and AC-side link faults. In other words, the fault on the AC side will trigger only an AC switchover, and the fault on the public network will trigger only a PW switchover.
• Independent mode: The primary and secondary PWs are determined by means of negotiation. Two PWs are configured on one PE to connect to two peer PEs, with both PWs being in the master state on the local device. The peer PEs determine the primary and secondary PWs by means of E-Trunk or mVRRP. The PEs on both ends then negotiate and finally determine the primary PW.The independent mode applies to scenarios where PW redundancy is associated with E-Trunk. The independent PW redundancy mode, together with the bypass PW, can prevent links on the AC side from sensing faults on the network side but cannot prevent links on the network side from sensing faults on the AC side. In other words, the fault on the public network will trigger only a PW switchover but not an AC link switchover, whereas the fault on the AC side will trigger both an AC switchover and a PW switchover.

Precautions

The independent or master/slave PW redundancy mode is used in PWE3 only.

If the mpls l2vpn redundancy command is run multiple times, the latest configuration overrides previous ones. The undo mpls l2vpn redundancy command restores the FRR mode. When using the undo mpls l2vpn redundancy command, ensure that the parameter in this command is the same as that in the corresponding mpls l2vpn redundancy command.

You can run the mpls l2vpn reroute command to configure a switchback policy for the VLL FRR or master/slave PW redundancy mode. By default, the delayed switchback mode is used. The independent PW redundancy mode uses only the immediate switchback mode.