Fanout, Replication, and Buffer Sizing for a Class of Self-Routing Packet-Switched Multistage Photonic Switch Fabrics
Ashok V. Krishnamoorthy, Fouad E. Kiamilev · 1995
We present the Stretch multistage switch; a class of self-routing multistage interconnection networks that provides a continuous performance-cost tradeoff between two of its degenerate forms: the Knockout switch1 and the Tandem banyan network2. Stretch networks utilize simple destination tag routing and can be designed to achieve low delay and arbitrarily low blocking probabilities for random, permutation, and non-uniform traffic without using internal buffers in the switches. These qualities make them useful for both fast packet (ATM) switching and multiprocessor architectures. The flexibility of the architecture helps the designer to accommodate user requirements in terms of packet loss probabilities while allowing the structure of network to be driven by technology considerations. The advantages of the Stretch multistage switching fabric come to bear in cases where the number of channels is very large and the ability to use fanout in the network is available. These considerations make it a good candidate for a photonic implementation. In this paper, we discuss the design of switch fabric and suggest a possible photonic switch implementation.