Title: Providing Fairness Through Detection and Preferential Dropping of High Bandwidth Unresponsive Flows

When: Thursday, July 29, 2004, 10:00 AM - 12:00 PM

Where: Room 503 IS Building

Who: Gwyn Chatranon

Committee: Dr. Sujata Banerjee, Hewlett-Packard Laboratories, and
Telecommunications program, University of Pittsburgh
Dr. David Tipper
Telecommunications program, University of Pittsburgh
Dr. Richard Thompson,
Telecommunications program, University of Pittsburgh
Dr. Jose Carlos Brustoloni
School of Computer Sciences, University of Pittsburgh
Dr. Miguel Labrador
Computer Science & Engineering, University of South Florida

Abstract: Stability of the Internet today depends largely on cooperation between end hosts that employ TCP that back off with network congestion. However, various types of traffic, including streaming media applications, are increasingly deployed. Such types of traffic usually do not employ end-to-end congestion control mechanism and could create an unfairness and congestion collapse problem. To avoid substantial memory requirement and complexity, fair Active Queue Management (AQM) utilizing no or partial flow state information were proposed recently to solve these problems. These schemes however exhibit several problems under different circumstances.

This dissertation presents two fair AQM mechanisms, BLACK and AFC, that overcome the problems and the limitations of the existing schemes. Both BLACK and AFC need to store only a small amount of memory to maintain and exercises its fairness mechanism. Simulation studies show that both schemes outperform the other schemes in a large number of scenarios. This research also includes the comparative study of the existing techniques to estimate the number of active flows which is a crucial component for some fair AQM schemes. Further contribution presented in this dissertation is the evaluation of fair AQM schemes under the presence of various type of TCP friendly traffic which show that some fair AQM schemes that work well with UDP, may get inferior performance with TCP-friendly traffic.