ALOHA/slotted-CSMA protocol for a very high-speed optical fiber local area network using passive star topology

A protocol for a multiuser very high-speed optical data network based on a passive star topology is presented and analyzed. The users´ traffic is assumed to be bursty as in the case of computer communications. Tunable transmitters and receivers which are capable of tuning to N+1 relatively stable wavelengths are required to be cross-connected via a passive optical star coupler to the other users of the network. One of the N+1 wavelengths is used to provide the switching information to the receivers and the others are used for actual data transmission. The protocol employs the pure ALOHA random access scheme on the control channel and the slotted-CSMA (carrier sense multiple access). Numerical results for different values of wavelength number, propagation delay time and data packet length show that for large ratios of the length of a data packet to a control packet and for heavy traffic conditions, the protocol achieves a higher throughput and causes much less delay