Performance of multiple access protocols for local lightwave networks with a single-hop topology

Abstract

In this dissertation work, we consider two multiple access protocols for a star LAN with a single-hop architecture. One is related to the access protocol for the WDM-based local network with star topology. Since a WDM network is a multichannel network, it is important to develop a proper protocol to have efficiently the multichannel operation. The other is related to the ICMA/CD protocol for a packet radio LAN. First, we propose an asynchronous reservation protocol in a WDM-based local network for efficient transmission variable-sized messages. With this protocol, if a node successfully acquires a data channel, the node exclusively reserves the data channel until the message is completely transmitted. Moreover, the protocol is independent of the change of the number of nodes, and it can avoid data channel and destination conflicts. Random and idle schemes are considered for the data channel selection strategies. We analyze the performance of the protocol by using an equilibrium point analysis (EPA) method with the assumption of infinite node population, and validate it by simulation. According to the analysis results, we find that the proposed protocol is effective in achieving significant performance improvement over other protocols so far proposed. By numerical analysis, we also show that the idle scheme yields higher throughput at lower offered load, while the random selection scheme works well at higher offered load. Second, we propose a synchronous reservation protocol for variable-sized messages in a WDM-based local network. The synchronous system is more efficient than an asynchronous system, because it reduces the overhead for synchronization. Moreover, in the synchronous system, the number of uncollided control packets which fail in acquiring a data channel due to the possibility of data channel and/or destination conflict is reduced, thus yielding better performance. We consider two cases separately, according to whether or not the slot size is larger...