Performance of multihop communications using logical topologies on optical torus networks

We consider multihop communications on optical torus networks with time-division multiplexing where logical topologies are realized on top of the physical network to improve the communication performance. The logical topologies reduce the number of intermediate hops at the cost of a larger multiplexing degree. On the one hand, the larger multiplexing degree increases the packet communication time between hops. On the other hand, reducing the number of intermediate hops reduces the time spent at intermediate hops. We study the trade-off between the multiplexing degree and the number of intermediate hops. Specifically, we study four logical topologies ranging from the most dense logical all-to-all connections to the simplest logical torus topology on top of physical torus networks. We develop an analytical model that models the maximum throughput and the average packet delay of the multihop networks, verify the model through simulations, and study the performance and the impact of system parameters on the performance for these four topologies.