MAC protocols and fairness control in WDM multirings with tunable transmitters and fixed receivers

The paper illustrates novel proposals for medium access control protocols in all-optical packet networks based on WDM multichannel ring topologies where nodes are equipped with one fixed-wavelength receiver and one wavelength-tunable transmitter. Such networks provide separate slotted channels for disjoint subsets of destination nodes. Three access protocols based on local status information are described. A channel inspection capability is assumed to be available for the implementation of the access protocols. Global fairness control algorithms derived from those adopted in the Metaring high-speed metropolitan area network are also proposed. Access delays and throughputs are taken as performance Indices for a simulation-based comparison of the proposed protocols, in the case of a 16-node multiring with either balanced or unbalanced traffic. Simulation results show that the throughput limitations and the fairness problems inherent in the network topology can be overcome with relatively simple protocols.