An SDN-driven approach to a flat Layer-2 telecommunications network

In this paper, we propose a design for a flat Layer 2 Metro-Core network as part of a Long Reach PON architecture that meets the demands of scalability, efficiency and economy within a modern telecommunications network. We introduce the concept of Mac Address Translation, which is equivalent to Network Address translation at Layer 3 but applied instead to layer 2. This allows layer 2 address space to be structured and fits well with the table driven approach of OpenFlow and the wider Software Defined Networks. Without structure at the layer 2 addressing level, the number of flow table rules to support a moderately sized layer 2 network would be very significant, for which there are few if any OpenFlow switch available with adequate TCAM tables.