Abstract

The increasing gap between the growth of datacenter traffic and electrical switch capacity is expected to worsen due to the slowdown of Moore’s law, motivating the need for a new switching technology for the post-Moore’s law era. We have been developing Sirius, an optically-switched network for datacenters providing the abstraction of a single, high-radix switch that can connect thousands of nodes—racks or servers—in a datacenter while achieving nanosecond-granularity reconfiguration. At its core, Sirius uses a combination of tunable lasers and simple, passive gratings that route light based on its wavelength. In this talk, I will describe how Sirius’ switching technology and topology is tightly codesigned with its routing and scheduling and with novel congestion-control and time-synchronization mechanisms to achieve a scalable yet flat network that can offer high bandwidth and very low end-to-end latency. Our small-scale Sirius prototype, using a custom tunable laser chip that can tune in less than a nanosecond, demonstrates end-to-end optical switching in 3.84ns.

Bio: Hitesh Ballani is a Senior Principal Researcher at Microsoft Research in Cambridge, UK. His research aims to build systems and networks for next-generation data centers. His current focus is on developing optical technologies for the cloud. Previously, he worked on a Quality-of-Service architecture for networked storage that ships in Windows Server. He graduated with a PhD in Computer Science from Cornell University in 2009 and then joined Microsoft.