Multiconfiguration multihop protocols: A new class of protocols for packet-switched WDM optical networks

Wavelength-division multiplexing (WDM) local-area networks based on the opt ical passive-star coupler have traditionally been classified as being eithe r single-hop or multihop, A single-hop network provides a direct connection between the source and the destination of a packet during the packet trans fer duration, but may require some amount of coordination between the nodes which may involve tuning of the transmitters or receivers at each node. Si nce the time required to tune a tunable optical transmitter or receiver may be high, a single-hop network may incur significant overhead. On the other hand, a typical multihop network requires little or no tuning, but a packe t may traverse a number of intermediate nodes between the source and destin ation nodes. Each hop incurs additional queueing delays at each node and al so increases the overall load on each link and on the network, In this pape r, we propose a new class of multiconfiguration multihop protocols (MMPs) w hich use tunable transmitters and receivers to cycle through a number of co nfigurations which together make up a multihop logical topology, This class of protocols offers a trade-off between the tuning required in a single-ho p network and the number of hops required in a multihop network, We present a generalized framework for comparing the proposed protocols with existing single-hop and multihop protocols, and we show that these protocols may of fer significant performance gains for systems with high tuning delays and a limited number of transmitters and receivers at each node.