THE PACKET ADM - ADDING RPR AND MPLS TO EXISTING SONET NETWORKS - WHY AND HOW?

摘要

We have reviewed the building blocks of a packetized transport architecture that can support the existing high-revenue TDM/SONET-based services, and carry them in a way that takes into account their packet nature. Such a packetized transport architecture uses standard SONET as its PHY, along with new SONET technologies like VCAT, LCAS and GFP to allow it to seamlessly interwork with the existing SONET-based installed based, and enable the provisioning of a virtual packetized transport network over spare capacity in an existing SONET network. It also uses the RPR MAC as a common per-class-of-service traffic management layer on a shared media ring that enables bandwidth utilization through statistical multiplexing, overbooking and spatial reuse. A packetized transport network uses standards-based MPLS as its common control plane layer to carry all services as standard pseudo-wires over the shared packetized network. MPLS also allows service providers to perform traffic engineering, user segregation, and end-to-end automatic provisioning across networks. Packet ADMs constitute the main building blocks of a packetized transport paradigm. They are designed to bring packet efficiencies and cost-effectiveness to today's SONET-centric transport networks.