Enhancing OSPF to provide adaptive traffic distribution with networks for improved QoS performance

In recent years the growth in demand for multimedia applications delivered over anetwork has been extensive illustrated by the phenomenal expansion of the World WideWeb in today's Internet. Increasing amounts of electronic information are presented ina multimedia format and delivered over networks, which generates increased trafficdemands. In short, future networks will not only comprise multiple, interconnected datatransport platforms but will also need to handle an increasing range of distributedmultimedia services, delivered to a diverse user community that is increasinglybecoming mobile.However, this vision can only be realised if the underlying network infrastructure iscapable of providing the appropriate Quality of Service (QoS) guarantees. The onlylimitation is that bandwidth will always remain a finite resource and whilst 'throwingbandwidth' at the network may provide short-term relief, in the medium and long term,users grow their demand to equal and finally surpass the capacity of the network.As the network is a finite resource, effective usage is very important withoutcompromising the applications in the process. Thus, a substantial body of research isbeing conducted into the development of QoS routing policies, which are able to directtraffic over a connectionless, best effort delivery platform whilst trying to satisfy theend-to-end application's QoS requirements.In existing IP data networks, routing is concerned with connectivity and typicallysupports only one type of datagram service called "Best Effort Routing". Routingprotocols such as OSPF in the main only use shortest-path algorithms and an arbitrarysingle metric such as hop count, for optimal path computation. Therefore, routingprotocols need to have a more complex model to support QoS requirements. The basicproblem of QoS-based routing is then to find a path that satisfies multiple QoSconstraints and resource utilisation efficiency.This thesis reports on research work that has investigated how OSPF can be enhanced toprovide an adaptive traffic routing algorithm that aims to assign, and dynamically reassign,traffic flows to routes based on current utilisation. In this way overall traffic canbe more efficiently distributed across the network topology, thereby delaying the onsetof congestion and improving overall end-to-end delay times. A new traffic distributionalgorithm has been developed and integrated within OSPF. This, in turn, has beensimulated using the OPNET Modeler® simulator and proven to offer improved QoSperformance over standard OSPF. Studies have also been carried out to evaluatebehavioural characteristics of the new algorithm resulting from the dynamic reassignmentof traffic flows. Whilst the implementation has concentrated on OSPF, thework has broader application to other routing protocols.In conclusion, a new adaptive traffic distribution algorithm is proposed to enhance theperformance of OSPF and hence, contribute to the broader body of knowledge in fieldof QoS based routing