http://www.rfc-editor.org/rfc/rfc4664.txt
RFC 4664: Framework for Layer 2 Virtual Private Networks (L2VPNs), L. Andersson, E. Rosen2006-09-01T23:00:00-00:00This document provides a framework for Layer 2 Provider Provisioned Virtual Private Networks (L2VPNs). This framework is intended to aid in standardizing protocols and mechanisms to support interoperable L2VPNs. This memo provides information for the Internet community.