The ''packing'' and the ''scheduling'' packet switch architectures for almost-all optical lossless networks

We propose two almost-all optical packet switch architectures, called the Packing Switch and the Scheduling Switch, which when combined with appropriate wait-for-reservation or tell-and-go connection and flow control protocols provide lossless communication for traffic that satisfies certain smoothness properties. Both switch architectures preserve the order of packets that use a given input-output pair, and are consistent with virtual circuit switching. We find a lower bound on the number of elementary (2-state) switches required by any switch architecture to meet the objectives we have set. The number of 2-state switches used in the Scheduling Switch is of the optimal order jointly with respect to the number of inputs and with respect to the burstiness of the traffic streams (as measured by an appropriate parameter). The Packing Switch requires very little processing of the packet header, and uses a number of 2-state switches that is of the optimal order in terms of the burstiness parameter. We also examine the suitability of the proposed switches for the design of circuit switched networks. We find that the Scheduling Switch combines low hardware cost with little processing requirements at the nodes, and is an attractive architecture for both packet-switched and circuit-switched high-speed networks.