2010 Poster Sessions : Achieving Practical Reliable Multicast with TCP-SMO

Student Name : Michael Chan
Advisor : David Cheriton
Research Areas: Computer Systems
Many networked applications, such as software updates and multimedia distribution, require delivery of data to multiple receivers. Reliable multicast transport protocols have been developed to this end. They are designed for the very large scale (tens of thousands to hundreds of thousands of receivers) and each presents a different set of tradeoffs. As a result, they tend to be complex and it is difficult to persuade users to adopt a specific solution. Besides, there has not been a compelling application that necessitates such huge-scale multicast, so none of the protocols has seen widespread deployment. Instead, contemporary solutions rely on establishing individual (TCP) connections between the sender and receivers, i.e. application-level multicast. Such schemes, however, forgo optimization opportunities using network-layer multicast. We believe that network-layer multicast is a significant local optimization, and that one can scale system-level multicast using application-level techniques. In this poster, we present a single-source multicast optimization (SMO) extension to TCP for efficient medium-scale reliable network-layer multicast (for up to a thousand receivers). SMO requires modest changes to the end host and exports a familiar API to user programs, thus facilitating deployment. Early results show significant bandwidth savings over using unicast alone. We also discuss application-level techniques to achieve large scale and multiple senders.

Michael Chan is a PhD student in the Distributed Systems Group of Stanford University's Computer Science department. His research interests are in networking and distributed systems. He is currently working on TCP extensions in the Linux kernel's networking stack to enhance transport-layer services for large-scale distributed applications. He was previously involved in the OpenRoads project and was responsible for building kernel modules for client-side network mobility solutions. He obtained his Bachelor's and Master's Degrees in Computer Engineering and Computer Science respectively at the Hong Kong University of Science and Technology.