Quality of Service Routing: A Multi-Path Approach

The demand of real time multimedia applications have been increased in today’s scenario of Internet .To fulfil this requirement, Quality of Service(QoS)factors have become necessary to be present in the network. For example, transmission of video over a computer network should be without undesirable delay, jitter and a medical image or a robot control packet may be required to be transmitted over a network with the minimum end-to-end delay. The present Internet routing mechanisms (based on the best-effort paradigm) are unlikely to provide such end to- end performance guarantees requisite in these applications. Here is a need of the mechanism which will consider these factors (delay, jitter, bandwidth etc.) for the transmission. One of the components of that mechanism is QoS routing. Multipath approach can be merged into QoS Routing to catch its maximum advantage as in some situation a single path is not able to fulfil all the QoS requirements. The benefits of provisioning multiple QoS paths are reliable QoS support and uniformly balanced network load. This paper describes an approach based on identifying multiple paths to provide QoS routing. A source routing algorithm has been presented in this paper. The algorithm is an extension to the algorithm proposed by Wang & Crowcroft (Wang et al, 1996). The algorithm proposed by (Wang et al, 1996) finds a single path which satisfies QoS parameters-residual bandwidth and propagation delay and finds a bandwidth-delay constrained path. The algorithm first eliminates all the links that do not meet the bandwidth requirement. Then it finds the minimum delay path from source to destination using Dijkstra algorithm. A multipath extension to this algorithm i.e. M-Bandwidth-Delay constrained algorithm has been proposed in this paper. The algorithm has been implemented in MATLAB and the results obtained have also been presented.