Delay Analysis and Queue-Length Distribution of a Slotted Metro Network Using Embedded DTMC

In this paper, we investigate performance analysis on queuing delay and queue length distribution of a slotted bus-based optical metropolitan area network (MAN) using fixed length packet format and a single wavelength. The studied network is a unidirectional bus on which many access nodes are connected to transmit fixed length packets to a centralized Hub node over a single wavelength. Each access node is modeled by an embedded discrete time Markov chain (EDTMC). The solution of this EDTMC allows computing the approximate probability that the next downstream access node on the bus sees the slot free. By using the recurrent analysis technique, we outline an approximate queue-length distribution as well as an approximate mean waiting time for each access node. The analytical results are finally compared with the simulation results. We have seen that the results strongly depend on the typical number of access nodes in the network. Both simulation and analytic models capture the expected behavior of mean waiting time and queue-length distribution but the difference between two models becomes more important as the transmission priority of ring node decreases.