IETF RFC 7392 PDF

When set up through an explicit path, dynamic Multi-Segment Pseudowires (MS-PWs) may be required to provide a simple solution for 1:1 protection with diverse primary and backup MS-PWs for a service, or to enable controlled signaling (strict or loose) for special MSPWs. This document specifies the extensions and procedures required to enable dynamic MS-PWs to be established along explicit paths.