Ethernet over WDM: Optimization for resilience and scalability

The emerging Ethernet technologies deployed in metro networks provide services based on pure Ethernet. Low cost optical Ethernet interfaces are used to interconnect different sites. Then, the use of wavelength division multiplexing technology with optical Ethernet is clearly the next step in building cost efficient metro networks. In this paper we propose a novel architecture and configuration methods that make metro Ethernet better scale to larger traffic and to covering larger areas that consist of more nodes promising significantly lower costs. The idea is to utilize wavelength paths optimally for bypassing certain Ethernet nodes and by employing traffic grooming according to different strategies we propose and compare. The result is always a tradeoff between the cost of the solution and the achievable throughput. Our methods are based on integer linear program and combinatorial heuristics. The proposed architecture and the optimization framework support very fast recovery upon a failure. Furthermore, it handles the shared risk link groups to ensure that the working and the backup paths should be physically disjoint. The method also supports traffic engineering goals: network utilization and resilience. Furthermore, it can be well used to enforce limitations on the depth and diameter of the obtained logical topology that allows scalability.