An L2VPN (Layer 2 Virtual Private Network) multi-segment pseudowire (MS-PW), also called a switched PW, is a statically- or dynamically-configured set of two or more PW segments that function as a single PW. An MS-PW spans across multiple cores or autonomous systems of the same or different carrier networks.

Multi-segment pseudowires enable a service provider to extend the reach of pseudo-wires across multiple domains. The domains can be autonomous systems under one provider administrative control, IGP areas in one autonomous system, different autonomous systems under the administrative control of two or more service providers, or administratively established pseudowire domains.

The end routers are called terminating PE routers (T-PEs), and the switching routers are called S-PE routers. The S-PE router terminates the tunnels of the preceding and succeeding PW segments in an MS-PW.

The S-PE router switches the control and data planes of the preceding and succeeding PW segments of the MS-PW. An MS-PW is declared to be up when all the single-segment PWs are up.

This document contains the procedures required to accomplish the following tasks: