Performance Impact of Switching Latency on WDMA Protocols

This paper investigates the impact of fast wavelength tunable device switching latency on the performance of media access protocols for star-coupled wavelength-division multiplexed photonic networks. The relative impact with a reservation based protocol (TDMA-C) and two pre-allocation based protocols (I-TDMA* and I-SA) are compared. TDMA-C is control channel based, with one WDM channel allocated to reserve access for data packet transmission on the remaining data channels. Control channel access arbitration is achieved through time-division multiplexing, enabling all active nodes the opportunity to transmit once every control cycle. I-SA and I-TDMA* are designed for a network where channels are pre-allocated to the nodes for reception where each node has a home channel it uses for all data packet receptions. The performance of the protocols is evaluated through discrete-event simulation in terms of network throughput and average packet delay. In particular, this paper examines the performance impact with variations in the number of nodes and data channels, packet generation rate, data packet length, and optical device switching latencies.