12:45 PM, Thursday, October 10th, 2002
Room 104, Gates Computer Science Building

Analysis of a Campus-wide Wireless Network

David Kotz
Dartmouth College

About the talk:

Understanding usage patterns in wireless local-area networks (WLANs) is critical for those who develop, deploy, and manage WLAN technology, as well as those who develop systems and application software for wireless networks. This paper presents results from the largest and most comprehensive trace of network activity in a large, production wireless LAN.

For eleven weeks we traced the activity of nearly two thousand users drawn from a general campus population, using a campus-wide network of 476 access points spread over 161 buildings. Our study expands on those done by Tang and Baker, with a significantly larger and broader population. We found that residential traffic dominated all other traffic, particularly in residences populated by newer students; students are increasingly choosing a wireless laptop as their primary computer. Although web protocols were the single largest component of traffic volume, network backup and file sharing contributed an unexpectedly large amount to the traffic. Although there was some roaming within a network session, we were surprised by the number of situations in which cards roamed excessively, unable to settle on one access point. Cross-subnet roams were an especial problem, because they broke IP connections, indicating the need for solutions that avoid or accommodate such roams.

[Joint work with Kobby Essien]

About the speaker:

David Kotz is an Associate Professor of Computer Science at Dartmouth College in Hanover NH. He received the M.S. and Ph.D degrees in computer science from Duke University in 1989 and 1991, respectively. He received the A.B. degree in computer science and physics from Dartmouth College, Hanover NH, in 1986. He rejoined Dartmouth College in 1991 and was promoted with tenure to Associate Professor in 1997. His research interests include context-aware mobile computing, intrusion detection, multiprocessor file systems, and mobile agents. He is chair of ACM SIGOPS, and a member of the ACM, IEEE Computer Society, and USENIX associations, and of Computer Professionals for Social Responsibility.