Distributed optical ATM switching architectures

We propose a new class of distributed optical ATM switching architectures for wide-area networks. The networks consist of geographically distributed group routing nodes (GRNs) connected by WDM links in different topologies. Individual users, such as LANs or high performance computers, are attached to each GRN. A GRN consists of routing modules (RMs), each of which contains a small number of fixed wavelength transmitters and passive wavelength demultiplexed receivers determined by network topology, and serves both as a user interface and a router. Each GRN-to-GRN connection operates asynchronously via a passive star coupler, a WDM group link and a splitter connected to diffraction based passive wavelength demultiplexers in the RMs. A protocol utilizing WDM and bit level TDM is used for the pretransmission coordination, load-balancing and data transfer. Proposed networks with their protocol allow efficient network-wide broadcasts and multicasts and also perform well under nonuniform traffic in addition to uniform traffic. The interconnection topology is flexible and can be chosen based on traffic patterns.