http://www.rfc-editor.org/rfc/rfc7275.txt
RFC 7275: Inter-Chassis Communication Protocol for Layer 2 Virtual Private Network (L2VPN) Provider Edge (PE) Redundancy, L. Martini, S. Salam, A. Sajassi, M. Bocci, S. Matsushima, T. Nadeau2014-06-01T23:00:00-00:00This document specifies an Inter-Chassis Communication Protocol (ICCP) that enables Provider Edge (PE) device redundancy for Virtual Private Wire Service (VPWS) and Virtual Private LAN Service (VPLS) applications. The protocol runs within a set of two or more PEs, forming a Redundancy Group, for the purpose of synchronizing data among the systems. It accommodates multi-chassis attachment circuit redundancy mechanisms as well as pseudowire redundancy mechanisms.