Protocols for optical WDM metropolitan area networks

In this dissertation we present a network architecture that combines the advantages of optical communication technologies with that of electronic processing. The network architecture consists of an optical backbone network interconnecting many Mesh Local Area Networks (Mesh LANs). The Mesh LANs use networking techniques like a form of virtual cut through routing, source routing and hop-by-hop congestion control in a mesh network formed by switches connected in an arbitrary fashion. The optical backbone network is a broadcast-and-select star coupler based architecture which uses wavelength division Multiplexing (WDM) to provide large amount of bandwidth (per session connection of upto 1 Gbps) in the individual fiber and provides a total throughput in the order of several tens of hundreds of Gbps.; For the above architecture, the networking issues in both the Mesh LANs (e.g., congest ion control) and the optical backbone network are of interest to us. Here we study only the protocols relevant for the optical backbone network. We present a multiple access protocol called Group Time Division Multiplexing (GTDM) which makes use of a control channel and a number of data channels. We show that this scheme performs better than another scheme called the Hybrid TDM. Both of these above schemes combine the features of Time Division Multiplexing (TDM) and a distributed scheduling scheme called Dynamic Allocation Scheme (DAS).; The above proposed protocol needs synchronization on the data channels which is usually difficult to achieve in networks spanning metropolitan area distances. Also, we would like to improve the performance of the network under low load conditions. In this dissertation, we propose a random access protocol that transmits packets after announcing it on the control channel and retransmit if collisions occur. We found that by monitoring the control channel, the number of collisions for the messages can be kept to a minimum. Simulation of the random access protocol yielded the maximum throughput on a wavelength channel to be 58%.; We also present a hierarchical two-level star coupler architecture and show how the GTDM protocol can be extended to work in the hierarchical system.