Hierarchical routing in layered ring and mesh optical networks

– We consider hierarchical optical networks with different granularities of paths (wavelengths and wavebands). We introduce classification layers for routing models in these networks (separated and integrated routing, homogeneous and heterogeneous networks, online and offline routing). We also propose and analyze two heuristic routing and aggregation algorithms (online and offline) to be used for homogeneous networks in the separate routing framework. The analysis is based on ring topology; its results are supported by simulations of large scale networks (European and US). These simulations demonstrate a significant cost reduction achieved by employing hierarchical routing (from 33% in online algorithm to almost 60% in offline one).