Implementing priorities in multiaccess protocols for optical fiber-based local area netorks
Thien Vo-Dai · ACM SIGCOMM Computer Communication Review · 1986
Most recently proposed optical fiber-based LAN architectures may be considered as different implementations of the basic round-robin transmission service in different topologies using special signal patterns or events to achieve the effect of the token passing protocol. Prioritizing the transmission of various data and control messages is necessary for time-critical applications (e.g. in data sensor or process control applications). Some extensions of the basic CSMA-CD protocol to handle packet priorities have been proposed for bidirectional channels but prioritized multiaccess protocols taking advantage of the unidirectional property of optical channels do not appear to be widely available yet. The main thrust of this paper is to propose some distributed prioritized multiaccess protocols for twin-bus optical channels. We will introduce two prioritized protocols: one uses the token packet to convey and enforce priorities and the other employs time-outs to achieve prioritization. Our protocols require only backlogged stations to be active.