Framework for IP/MPLS-GMPLS interworking in support of IP/MPLS to GMPLS migration

MPLS to GMPLS migration is the process of evolving MPLS-TE-based control plane to GMPLS-based control plane. An appropriate migration strategy is selected based on various factors including the service provider's network deployment plan, customer demand, available network equipment implementation, etc. In the course of migration several interworking cases may exist where MPLS and GMPLS devices or networks must coexist. Such cases may arise as parts of the network are converted from MPLS protocols to GMPLS protocols, or may occur if a lower layer network is made GMPLS- capable (from having no MPLS or GMPLS control plane) in advance of the migration of the higher layer packet switched layer. Since GMPLS signaling and routing protocols are different from the MPLS protocols, in order for MPLS and GMPLS to interwork, we need mechanisms to compensate for the difference between MPLS and GMPLS. This document provides a framework for MPLS and GMPLS interworking to allow transition from MPLS to GMPLS. We discuss issues, models, migration scenarios, and requirements. Solutions for MPLS and GMPLS interworking will be developed in companion documents. We should note that both MPLS and GMPLS protocols can co-exist as ships in the night without any interworking issue. This document is mainly addressing interworking to allow transition from MPLS to GMPLS.