On the Offline Physical Layer Impairment Aware RWA algorithms in transparent optical networks: State-of-the-art and beyond

In transparent optical networks with no regeneration, the problem of capacity allocation to traffic demands is called ldquorouting and wavelength assignmentrdquo. Much work on this topic recently has focused on the dynamic case, whereby demands arrive and must be served in real-time. In addition, due to lack of regeneration, physical impairments accumulate as light propagates and QoT may become inappropriate (e.g., too high bit error rate). Considering the physical layer impairments in the network planning phase gives rise to a class of RWA algorithms: offline physical layer impairment aware - (PLIA-)RWA. This paper makes a survey of such algorithms, proposes a taxonomy, and a comparison between these algorithms for common metrics. We also propose a novel offline PLIA-RWA algorithm, called POLIO-RWA, and show through simulations that it decreases blocking rate compared with other PLIA-RWA algorithms.