Sept '06-Aug '08 — Master's in Computing Science, Simon Fraser University, Burnaby, B.C.

I began work on a Master's in Computing Science (thesis option) at Simon Fraser University in September of 2006. This is a change from my undergraduate work, in which my major was in Physics, though I did minor in Computing Science.

I chose Networking as the main area for my research, and further decided to focus on peer-to-peer networking. This has led me to choose Dr. Jiangchuan Liu as my supervisor, as he has contributed a lot of reasearch in this area, including the introduction of CoolStreaming.

My work is partially funded by an NSERC Canada Graduate Scholarship M, which I was awarded in March of 2007.


My current research is focussed mainly on BitTorrent. One aspect I have studied is the effectiveness of the rarest-first policy to evenly distribute pieces of the download throughout the peers. I have found that the policy is mostly effective at maintaining a near-optimal piece population distribution, though there are some areas for improvement.

I have also examined the different network topologies formed between peers in a BitTorrent swarm. Some of the networks I have found to have scale-free behaviour, verifying the resilience of the swarm to the failures and departures that are common in all peer-to-peer networking scenarios. Others that were previously thought to have small-world characteristics, I have found to contain very little clustering. I have therefore designed an enhancement to the BitTorrent tracker to introduce clustering and create a small-world from the BitTorrent swarm, which should improve the effectiveness of the BitTorrent protocol at distributing the download to peers.

Using this work as a foundation, I am currently working on a new peer-to-peer download system for distributors of free content (mostly software packages) over the web. The system uses a Distributed Hash Table to support downloading the individual content files from peers, which reduces the strain on the network of mirrors that is usually required to support the downloads. This work includes implementing a new download client for software packages of Debian-based systems called apt-p2p.

To simulate and measure BitTorrent swarms, I have been able to use the PlanetLab network, a global co-operative research network in over 300 locations around the world that supports the development of new network services. For more information on this research, see my PlanetLab page.

In collaboration with another student, Xu Cheng, we have studied the video sharing site YouTube. This new type of video distribution has not seen much research yet, and we find some interesting differences between it and traditional video distribution. My work focussed mostly on the social networking aspect of YouTube, which is unique among video sharing sites. The results showed that YouTube videos form a small-world network, which suggests that videos are strongly correlated with each other. This feature can be used to develop interesting caching or peer-to-peer distribution strategies for videos.


The following papers have been submitted and accepted to conferences:

The following posters have been submitted and accepted to conferences:

My thesis was

List of Courses Completed

Discipline Number Course Name Grade
Computing Science 705 Design and Analysis of Computing Algorithms A
Computing Science 740 Database Systems A-
Computing Science 765 Computer Networks A+
Computing Science 816 Theory of Communication Networks A+
Computing Science 880 Special Topics: Multimedia & Sensor Networking A+