Bilkent University
Department of Computer Engineering


  Continuous Flow Routing (CFR): An Ad Hoc Routing Algorithm for Supporting Multimedia Flows


Ahmet Kara
Computer Engineering
Bilkent University

Multimedia flows require special routing layer support in ad hoc networks due their unique characteristics and certain requirements on packet delay, jitter, loss rate and bandwidth. In this thesis we propose a wireless ad hoc routing protocol (called CFR) with route discovery and maintenance mechanisms, that is specifically designed for better supporting multimedia flows in wireless ad hoc networks. Since multimedia flows are long durational, it is important to route them through stable routes in order to minimize route failures and disturbance on the flows. We propose to improve the stability by considering the energy drain rates and estimated remaining lifetimes of nodes while selected the best routes. Additionally we provide a maintenance scheme that acts pro-actively and re-routes the traffic if a node starts getting very low energy. For this define two thresholds on remaining lifetime of a node. After the first threshold is reached, the node re-routes some of its flows so that the traffic load on the node is reduced. This helps to an even distribution of traffic to nodes of an ad hoc network. After the second threshold is reached, the node has very few energy and therefore redirects all its traffic to some other routes so that the flows are not disturbed by the route failure when the node depletes all of its energy and can not route anymore. We implemented the protocol as part of an ns2-based simulator and proved that it works correctly. Additionally, we compared the protocol against some other similar protocols. The results show that CFR can indeed help supporting multimedia flows better.


DATE: July 28, 2006, Friday@ 14:00