http://www.rfc-editor.org/rfc/rfc6001.txt
RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions for Multi-Layer and Multi-Region Networks (MLN/MRN), D. Papadimitriou, M. Vigoureux, K. Shiomoto, D. Brungard, JL. Le Roux2010-10-01T23:00:00-00:00This document defines extensions to GMPLS routing and signaling protocols so as to support the operation of GMPLS Multi-Layer / Multi-Region Networks. It covers the elements of a single GMPLS control plane instance controlling multiple Label Switched Path (LSP) regions or layers within a single Traffic Engineering (TE) domain. [STANDARDS-TRACK]