Architecture and Analysis of Fast Packet Switches Based on Time-Multiplexed Photonic Fabrics

Abstract

This paper proposes and evaluates two fast packet switching architectures based on time-division multiplexed integrated photonic fabrics. The architectures are targeted towards low-latency inter-node switching and intra-node routing in high-speed networks. The inter-node switch achieves output packet queueing via asynchronous time-division multiplexing a strictly-nonblocking photonic fabric. Buffer behavior is analyzed at both input and output stages to.determine the effect of varying the switching bandwidth on the performance metrics (delay, throughput, and packet loss probability). Analysis is performed for finite switch dimensions by obtaining upper and lower bounds on the packet loss at input. The dependence of finite output buffer latency and overflow probability on the normalized switching bandwidth is examined. The intra-node trunk traffic router consists of a passive optical coupler followed by an active routing stage. For this architecture, both synchronous and asynchronous time-division multiplexing modes are modeled and analyzed to obtain expressions for corresponding packet buffering delay and total switching latency. The router is shown to saturate at the waiting time singularity of its input (or output) buffers, given by the ratio of the switching bandwidth to the dimension.