RESEARCH

Interests: My research interests include the design and analysis of computer networks and content distribution systems with main applications in overlay network creation and maintenance, service deployment, content routing, bulk data transfers, distributed caching, and network security. Statement: When confronted with complicated networking problems, I first try to temporarily peel off non-essential details to reveal the underlying fundamental computer science problem. Once I have obtained a firm understanding of the underlying core problems, I go up the reverse path, and progressively add back all the omitted details. At this point I usually switch from analytic techniques to experimental ones, that are powerful enough to accommodate all the detail of real-world networking problems. In most cases, I prefer developing real prototypes and resort to simulation mostly for scalability results.

Research Projects:

ISP-P2P collaboration: We design and evaluate a service, provided by an ISP, to improve the connectivity of P2P users based on the network information available to the ISP. Our results show that the performance gain for P2P users is significant and so is the reduction of transit cost for ISPs that deploy such a service. [2008-today] Delay Tolerant Bulk Transfers on the Internet: We design and evaluate scheduling algorithms, some assisted by network-attached storage, to transfer delay tolerant bulk data over the Internet with the most cost effective way. [2008-today] Selfish Neighbor Selection: We re-examine the problem of overlay network creation, taking into consideration the existence of selfish overlay nodes. We develop a general game-theoretic framework that provides a unified approach to modeling Neighbor Selection procedures on behalf of selfish nodes. To capitalize on the substantial performance improvement of best response wirings for overlay nodes, we design, deploy and evaluate, EGOIST, a Selfish Neighbor Selection inspired prototype. We also show the benefits Selfish Neighbor Selection may offers to applications. [2006-today] Distributed Facility Location: We design and evaluate distributed algorithms for scalable and efficient service deployment and migration. [2006-today]

Distributed Selfish Caching: We study resource allocation and sharing issues where the exposed resource is the storage of each (selfish) node, and the nodes cooperate using on-line caching algorithms. We identify the causes and implications of mistreatment in distributed caching groups, and we design a novel framework to mitigating mistreatment in such groups. [2005-2007] SEP: A Stable Election Protocol for clustered heterogeneous wireless sensor networks: We design and evaluate distributed leader election protocols to prolong the lifetime of heterogeneous wireless networks. [2003-2004] The effect of router buffer size on the transport protocols performance: We study the robustness of memory-reduced routers in the presence of aggressive high speed transport protocols for bulk data transfers. [2003-2005]

A Large Deviations approach to Statistical Traffic Anomaly Detection: We develop a Large Deviations framework to rigorously identify, in real-time, network anomalies by assessing deviations of empirical measures in computer networks. [2004-2008]

FUN

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