The authors present a model for the broadcast star network with collision avoidance switch and with multiple priority classes of messages. They also propose a service discipline which is easy to implement and exhibits relatively low variance of message delay. This service discipline, which is used to select a message among messages with the same class-index, is a combination of first-come first-served (FCFS) and random-order of service (ROS) disciplines, and it uses the priority fields in the message header. Then, the ready stations can be considered to form a distributed queue, and the entire system can be considered to form a priority M/G/1 queueing system with multiple server vacations. They analyze the model to obtain the distributions of the message delay for the proposed service discipline, and compare the results with that for the FCFS discipline. From numerical results, they show that the variance of the message delay for the proposed service discipline is almost the same as that for the FCFS discipline for any distribution of message length and also for any value of normalized propagation delay.>

The authors propose a multichannel lightwave network with a grouping property which exhibits better channel efficiency as the traffic is more likely within groups. The network also avoids both wavelength agility and pretransmission coordination problems. Two network topologies are considered. One is a multichannel lightwave network with full connection within groups. While it requires many receivers in each network interface unit (NIU) it exhibits low queuing delay and high network capacity. The other is a multichannel lightwave network with minimal connection within groups. While it gives relatively poor delay-throughput characteristics, a network can be constructed with each NIU having only two fixed-wavelength receivers. The network capacities and the mean queuing delays for the two network topologies are presented.>