Towards All-optical Circuit-switched Datacenter Network Cores: The Case for Mitigating Traffic Skewness at the Edge

Abstract

All-optical circuit switched network core is the holy grail for the next-generation datacenter architectures, as electrical packet switches are struggling to cope up with increasing challenges posed by the end of Moore's law. However, traffic skewness is the biggest enemy of such all-optical network cores comprising of a simple round-robin circuit-scheduling abstraction. Even though valiant load balancing can theoretically solve the problem, it falls short in most of the practical scenarios. In this paper, we point towards a new research direction to address the skewness problem: why not resolve most of the skewness at the network edge while keeping the optical core simple? This approach is fundamentally different and can potentially enable the all-optical network core to achieve good performance in practice. We discuss relevant strategies and envision that a holistic system design is necessary considering all these strategies together.