This document describes how to connect pseudowires (PWs) between different Packet Switched Network (PSN) domains or between two or more distinct PW control plane domains, where a control plane domain uses a common control plane protocol or instance of that protocol for a given PW. The different PW control plane domains may belong to independent autonomous systems, or the PSN technology is heterogeneous, or a PW might need to be aggregated at a specific PSN point. The PW packet data units are simply switched from one PW to another without changing the PW payload. [STANDARDS-TRACK]