PW redundancy is supported for static MPLS-TP pseudowires. However, instead of using T-LDP status signaling to signal the forwarding state of a PW, control channel status signaling is used.
The following PW redundancy scenarios are available:
MC-LAG with single and multi-segment PWs interconnecting the PEs.
The 7210 SAS-T can only act as T-PE when a multi-segment PW is used.
The 7210 SAS-R6 and 7210 SAS-R12 can act as T-PE or S-PE when a multi-segment PW is used.
Dual-homing of a VLL service into redundant IES or VPRN PEs (the IES and VPRN service is configured on the 7750 PEs), with active/standby PWs.
In this scenario, 7210 SAS originates the Epipe MPLS-TP PWs as a T-PE. 7210 SAS nodes cannot terminate a MPLS-TP PW in a IES or VPRN service.
Dual-homing of a VLL service into a VPLS with active/standby PWs.
In this scenario, 7210 SAS originates the Epipe MPLS-TP PWs as a T-PE. 7210 SAS-R6 and 7210 SAS-R12 nodes can terminate a MPLS-TP PW in a VPLS service.
Active/standby dual-homing into routed VPLS is not supported for MPLS-TP PWs.
It is possible to configure inter-chassis backup (ICB) PWs as static MPLS-TP PWs with MPLS-TP identifiers. Only MPLS-TP PWs are supported in the same endpoint. That is, PWs in an endpoint must either be all MPLS-TP, or none of them must be MPLS-TP. This implies that an ICB used in an endpoint for which other PWs are MPLS TP must also be configured as an MPLS-TP PW.
A fail over to a standby pseudowire is initiated based on the existing supported methods (For example, failure of the SDP).