Path switching in OBS networks

Abstract

We investigate the concept of path switching in optical burst switched (OBS) networks and its potential to reducing the overall burst drop probability. With path switching, each source maintains a list of alternate paths to each destination, and uses information regarding the recent congestion status of the network links to rank the paths; it then transmits bursts along the least congested path. We present a suite of path switching strategies, each utilizing a different type of information regarding the link congestion status, and evaluate them using simulation. Our results demonstrate that, in general, path switching outperforms shortest path routing, and, depending on the path strategy involved, the network topology, and the traffic pattern, this improvement can be significant. We also present a new framework for the development of hybrid path switching strategies, which make routing decisions based on a weighted combination of the decisions taken by several independent path switching strategies. We present two instances of such hybrid strategies, one that assigns static weights and one that dynamically adjusts the weights based on feedback from the network. © IFIP International Federation for Information Processing 2005.