Quality-of-service routing in IP networks

Multimedia applications such as video-conferencing, telemedicine, HDTV etc. have very stringent Quality of Service (QoS) demands and require a connection oriented service. For these applications, a path satisfying their requirements in terms of bandwidth, delay, buffer etc. needs to be found. As conventional IP routing is based only on hop counts, it is not suitable for multimedia applications. It is clear that, to route requests that have QoS requirements, existing routers should be made QoS aware and the packet forwarding should be based on QoS parameters. Also, routing protocols like OSPF and RIP must be extended suitably to facilitate QoS routing. The goal of QoS routing algorithms is to find a loop-less path satisfying a given set of constraints on parameters like bandwidth, delay, etc. The path selection process could return either the entire path to the destination or the best next hop for the request. The first case is called as Source routing and the second is referred to as Distributed routing. In this paper, we propose a new distributed QoS routing algorithm for unicast flows, which has a very low call establishment overhead. Our algorithm makes use of existing IP routing protocols like OSPF, RIP with minimal modifications.