Improving QoS for real-time interactive multimedia over the Internet using differentiated services

This research presents a new method which enhances the quality-of-service (QoS) and hence the response time of interactive multimedia over the Internet. A service class based on differentiated services mechanism has been developed. Evaluation of response time under different traffic conditions has been conducted via simulation. Since audio and video traffic have different needs, priority schemes for different types of interactive multimedia traffic have been studied to provide control and predictable service, and therefore, better quality of service.; The Differentiated Services mechanism is currently one of the leading approaches being developed to provide services (forwarding treatments) to aggregate traffic. It does so without the need for per-session signaling. DiffServ is also able to keep the maintenance of per-session state to core routers to a minimum, hence, providing scalability. A performance comparison of the new routing methods to the existing IP routers has been done using OPNET and the results are presented.; A topology that mimics the Internet backbone has been developed. Traffic were generated which simulates the real-time interactive multimedia and background traffic which simulates non-interactive multimedia traffic to mimic the Internet traffic. Network performances were evaluated with simulated traffic using OPNET. First, the simulation predicts performance of traditional Internet backbone without traffic engineering. When the network is lightly loaded, the response time for voice and video were in conformance with the minimum requirements in terms of end-to-end one-way delay. Traffic to the network were increased to the point were some links became congested. This caused build-up delay in queues in the core routers. Lower priority traffic was competing with higher priority traffic at the router queues. The response time exceeded the requirements set in the service level agreement which indicates a failure for multimedia delivery.; Second, the routers algorithm was modified to use the differentiated services approach. Traffic aggregates were differentiated based on the Differentiated Services Code Points (DSCP) assigned value. Critical-mission real-time interactive multimedia traffic was given priority over non-mission-critical traffic. Higher priority traffic was classified and conditioned at the boundary of the network and handled accordingly by the core routers. The network was simulated again under the same traffic pattern used in the previous case. Different queuing scheme scenarios were simulated in the core routers and their performance were compared.; With DiffServ implemented, QoS was guaranteed and response time metrics were met for all real time traffic and it has a small impact on delivery time for non-real time traffic.; The results of this research show that future development of DiffServ will increase the Internet efficiency and capacity to handle different traffic with different requirements, providing predictable and controlled service, and providing excellent quality to mission-critical applications like real-time interactive multimedia.