Comparison of protocols for high-speed optical fiber local area networks using WDM passive star topology

Two protocols based on the slotted Aloha technique are proposed for very high-speed optical fiber local area networks using wavelength division multiplexing (WDM) passive star topology. Without setting a separated control channel, the adopted architecture uses all channels for transmitting messages and allows a successful user in the control slot to transmit continuously all his packets for getting the high performance, until the end of his message. The throughput and delay of synchronous and asynchronous channel architecture are compared and analyzed by varying the maximum number of data packets that are able to transmit at once, the length of a data packet, the priority method given to the longest message or to the shortest message and the retransmission probability. The numerical analysis shows that the proposed protocols have better throughput and delay performances than the previous works using the slotted Aloha protocol