Grooming in SDH/WDM mesh networks for different traffic granularities

Efficient allocation of low bit rate traffic streams onto optical channels, frequently referred as traffic grooming, has become a major issue in optical transport networks. The paper studies resource utilization in an optical mesh network under different allocation strategies. Traffic grooming is done following two different strategies: optical end-to-end (transparent) and hop-by-hop (opaque). The first scenario is advantageous when connection request capacity approaches that of the optical channels. Hop-by-hop offers the advantage of allowing intermediate nodes to re-use an already active optical channel with free bandwidth. A comparison in terms of the number of line terminating equipment items (SDH ports) and the number of active optical channels (wavelengths) in a generic mesh network is provided. Quantitative results are obtained by means of simulation.