Leveraging Commodity Photonics to Reduce Datacenter Network Latency
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Most datacenter network (DCN) designs focus on maximizing bisection bandwidth rather than minimizing server-to-server latency. They are, therefore, ill-suited for important latency-sensitive applications, such as high performance computing, realtime analytic systems and high-frequency financial trading. Although there are a number of existing approaches to reduce network latency, they are only partially effective, workload dependent, and often require network protocol changes. In this thesis, we explore architectural approaches to building a low-latency DCN and introduce Quartz, a new optical design element consisting of a full mesh of switches connected by an optical ring. We can reduce the network latency of a hierarchical or random network by replacing portions of it with a Quartz ring. Our analysis shows that, in a standard 3-tier DCN, replacing high port-count core switches with Quartz can significantly reduce switching delays, and replacing groups of top-of-rack and aggregation switches with Quartz can significantly reduce congestion-related delays from cross-traffic. We overcome the complexity of wiring a complete mesh by using low-cost optical multiplexers that enable us to efficiently implement a logical mesh as a physical ring. We evaluate our performance using both simulations and a small working prototype. Our evaluation results confirm our analysis, and demonstrate that it is possible to build low-latency DCNs using inexpensive commodity elements without significant concessions to cost, scalability, or wiring complexity.
Cite this work
Yunpeng Liu (2014). Leveraging Commodity Photonics to Reduce Datacenter Network Latency. UWSpace. http://hdl.handle.net/10012/8495