P-Torus: wavelength-based switching in packet granularity for intra-data-center networks

In this work we introduce P-Torus, a wavelength switching architecture for intra-data-center networks that exploits optical-packet-based transport and is based on 2D torus interconnected clusters. P-Torus does not require optical buffers, as all buffering takes place at the end hosts. The proposed architecture combines torus connectivity richness, time-slotted operation, and efficient wavelength routing in order to provide single-hop, contentionless, and low-latency interconnection among all top-of-rack switches. Wavelength switching is performed in wavelength or waveband granularity with the use of fast wavelength-tunable transmitters, in compliance with the optimal solution of the routing and wavelength assignment problem of the generic torus topology. Numerical simulations are carried out to evaluate the latency and throughput performance of the proposed architecture. Results show that P-Torus exhibits low end-to-end latency and high throughput, even under a high load, in uniform and hot-spot traffic scenarios. This work also includes cost and power consumption analyses showing that P-Torus has significant benefits over other contemporary wavelength-based switching architectures. Comparative simulations and cost analysis validate that P-Torus provides a very good trade-off between performance and cost compared to other wavelength-based switching architectures targeting small to medium data centers, up to 10,000 servers. (C) 2019 Optical Society of America