Network and Service Interworking in Layer 2 VPNs over IP/MPLS

Matthew Bocci, Alcatel

Virtual Private Networks are a popular way for enterprises to interconnect remote sites. Traditionally, these are built based on Frame Relay, ATM or TDM private lines, using the service provider's ATM core network, and accounting for the majority of their data service revenues. However, the influences of a highly dynamic telecommunications market have raised demands for increased flexibility while controlling costs. New revenue opportunities are emerging for service providers to differentiate their offerings through IP VPNs and VPLS, while achieving operational efficiencies though convergence of all services on a common MPLS backbone. However, existing technologies such as ATM provide highly profitable services.  These must continue to be supported.

This tutorial will describe how network and service interworking are required to build layer 2 VPNs over IP/MPLS networks, with any-to-any
connectivity.  In particular, it describes the motivation, technology, and standards debates as follows:

- Motivation for convergence on a common MPLS network for both layer 2 and layer 3 services
- Requirements on the new converged network
- Network and service interworking architectures
- Control plane interworking: Review of the challenges and explanation of the pros and cons of different ways of interworking the control plane across the new converged network e.g. Extended PNNI, virtual trunks and SPVC-PWE3 interworking.
- Fault management interworking between different technologies across the new converged MPLS network.