ty. The queues, wherever they are located, are assumed to be 10 packets long. It is to be noted that while the queue length is an important parameter for the delay evaluation, in the evaluation of the saturation throughput, the queue dynamic can be neglected due to the fact that when the switch operation reaches steady state, the queues are always full. The last element on the simulation, routing through the switch fabric, is performed by evaluating all the available paths for all the packets directed toward the same output in the same time slot and choosing randomly both the packet to transmit and the path among those available. Since we are considering strictly nonblocking structures, interference between packets does not exist, but for the fact that they could have the same destination. The Banyan switch is an exception, but in that case the path is unique and the algorithm limits itself to choose the packet to be transmitted randomly. E.2 Crossbar Switch Fabric In order to evaluate the performance of a crossbar switch fabric, we have to decide how packets are stored when arriving at the fabric. There are two base possibilities: input queues and output queues. Appendix E: Space Division Switch Fabric Performance Evaluation FIGURE E.1 Scheme of an input buffered switch fabric (a) and of an output queued switch fabric (b). Our intention is to compare these two configurations shown in Figure E.1. Before any simulation, intuition tells us that output buffering should work better than input buffer- ing due to the fact that output buffering causes a packet to be stored in a queue only if the output line is effectively busy, while input buffering also creates a queue among packets that enter from the same input but are directed to different outputs. Another important distinction is based on the strategy to manage packets that arrive in front of a full queue coming from the remote source. The source can either discard them or resubmit them. In intermediate cases, a certain probability of resubmission can exist. The an