Latency Hiding Strategies Of Pre-allocation Based Media Access Protocols For WDM Photonic Networks

Media access protocols that de-emphasize the performance impact of propagation delay, packet processing and switching latency for an optically star-coupled system with pre-allocated WDMA channels are introduced and compared. The channels are pre-allocated to the nodes with this approach, where each node has a home channel that it uses either for all data packet transmission or reception. A home channel may be shared if the number of nodes exceeds the number of channels in the system. This approach does not require both tunable transmitters and tunable receivers per node. Each node has a tunable transmitter and a fixed receiver plus a set of queues (one per channel) that are used to avoid head-of-line effects. The performance of a generalized random access protocol is compared to a protocol based on interleaved time multiplexing. Both protocols are designed to operate in a multiple-channel multiple-access environment and require each node to possess a tunable transmitter and a fixed (or slow tunable) receiver. The impact of network size, number of channels, transmitter tuning time, propagation delay and packet processing time on protocol design and performance is extensively studied.