On the 7750 SR and 7450 ESS, the MPLS-TP supports lock instruct and loopback for PWs, including the ability to:
administratively lock a spoke SDP with MPLS-TP identifiers
divert traffic to and from an external device connected to a SAP
create a data path loopback on the corresponding PW at a downstream S-PE or T-PE that was not originally bound to the spoke SDP being tested
forward test traffic from an external test generator into an administratively locked PW, while simultaneously blocking the forwarding of user service traffic
MPLS-TP provides the ability to conduct test service throughput for PWs, through the configuration of a loopback on an administratively locked pseudowire. To conduct a service throughput test, an administrative lock is applied at each end of the PW. A test service that contains the SAP connected to the external device is used to inject test traffic into the PW. Lock request messaging is not supported.
A lock can be applied using the CLI or NMS. The forwarding state of the PW can be either active or standby.
After the PW is locked it can be put into loopback mode (for two way tests) so the ingress data path in the forward direction is cross connected to the egress data path in the reverse direction of the PW. The loopback can be configured through the CLI or NMS.
The PW loopback is created at the PW level, so everything under the PW label is looped back. This distinguishes a PW loopback from a service loopback, where only the native service packets are looped back.
The following MPLS-TP loopback configuration is supported:
An MPLS-TP loopback can be created for an Epipe, Cpipe, or Apipe VLL.
Test traffic can be inserted at an Epipe, Cpipe, or Apipe VLL endpoint or at an Epipe spoke-sdp termination on a VPLS interface.
For more information about configuring lock instruct and loopback for MPLS-TP Pseudowires see, the 7450 ESS, 7750 SR, 7950 XRS, and VSR Services Overview Guide and the 7450 ESS, 7750 SR, 7950 XRS, and VSR Layer 2 Services and EVPN Guide: VLL, VPLS, PBB, and EVPN.