Fordham University            The Jesuit University of New York

CIS Department Talk - May 31, 2007

The Department of Computer and Information Science & The Society of Computer Science Present

Speaker:Ellen Xiaolan Zhang, University of Massachusetts
Topic:Disruption Tolerant Networks: Performance and Mobility Trace Modling
Date:May 31, 2007 at 11:00am
Place:John Mulcahy Hall, Room 138


Disruption Tolerant Networks, where there is often no contemporaneous path from source node to destination node, present challenging networking scenarios. Routing in such networks has adopted so called "store-carry-forward" paradigm, examples include epidemic routing and its variations.

In this talk, I will first present a rigorous, unified framework based on Ordinary Differential Equations (OEDs) for studying performance of epidemic routing and its variations. Derived as limits of Markovian models under a natural scaling, the OEDs models yield closed-form expressions for several performance metrics, and a numerical solution complexity that does not increase with the number of nodes.

Then I will present a modeling study of mobility traces taken from UMassDieselNet, an operational bus-based DTN. I propose a rout-level model that captures the structures within the bus-to-bus contact process, and show that epidemic routing performance predicted by traces generated with this model are much closer to the actual performance that would be realized in the operational system aggregated model. This suggest that one must take care in choosing the right level of model granularity when modeling mobility-related measuring such as inter-contact times in DTN networks.

Last, I will Briefly describe other research works I have done in the areas of DTNs, and research I did in the area of multimedia streaming and VoIP network measurement.


Ellen Xiaolan Zhang received her MSc Degree in computer science from University of Massachusetts, Amherst in 2001 Her BA degree in computer science from Peking University, China in 1992. She is currently a Ph.D. candidate at the Computer Science Department at University of Massachusetts, Amherst. She has six years of industrial working experience, and has done her summer internship with Bell Labs, Alcatel-Lucent in 2004. Her research interests include wireless mobile networks, Delay Tolerant Networks, multimedia communication, the measurement, modeling and performance evaluation of computer system and network.

For more information, contact:
Ms. Diane Roche (718) 817-4480; (

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