University: Carleton University
Name of Sponsoring Professor: Michel Barbeau
Department: School of Computer Science

We are using OPNET for :

Research:

Satellite Specific Protocols

We are working on two specific satellite communications problems: i) satellite specific protocols for fair and efficient bandwidth assignment and ii) reliable transmission of information over satellite links. We study the transport of the traffic of applications with different characteristics and QoS requirements. The problem of QoS provisioning is a problem intimately related to the problem of congestion avoidance and control (CAC) which in turn is intimately related Medium Access Control (MAC). We develop approaches and protocols addressing CAC in a satellite environment. We look at mechanisms for mapping bandwidth requests with QoS characteristics, of application, to bandwidth assignments. We simulate with OPNET CAC approaches and protocols for the purpose of analysis of fairness and efficiency.

Network protocols designed to ensure reliability of transmission on terrestrial networks, e.g. TCP, do not operate efficiently over satellite links. Long delays and, relatively, poor link quality creates adverse effects on the channel throughput. The limited transmission window size, the slow start algorithm, and the TCP numberring scheme are the major limiting parameters in networks with high delay-bandwidth product such as satellite based networks.

A number of proposals have been made to improve TCP for use over satellite links. The objective of our research is to investigate possible solutions to the problem of reliable transmission over satellite links and to model, simulate with OPNET, and analyse the most promising ones.

Publications

J. Peng, P. Andreadis, C. Bélisle and M. Barbeau, Improving TCP Performance Over Long Delay Satellite Links, OPNETWORK 2001, Washington, 2001. (PDF)

J. Peng, Improving TCP Performance over Long Delay Satellite Links, Master Thesis, School of Computer Science, Carleton University, 2001. (PDF)