National Taiwan University of Science and Technology

With increasing demand for multicast multimedia communications, future networks are expected to provide an integrated service for transporting data packets with QoS guaranteed over current Internet infrastructure. Resource reservation schemes seem the most effective over the various methods proposed within ISPN (Integrated Services Packet Network). But the result of QoS negotiation and resource reservation during connection establishment may not remain ideal throughout the duration of a communication session. There are three reasons for this. First, user’s QoS requirement can be very flexible and easily changed. Second, the nature of real time application has a decisive influence on the required network resources and different real-time applications have quite different communication needs. Third, due to a continuously changing networking environment, network load may change significantly over the duration of the connection. In this thesis, we propose a framework for the networks to continuously monitor the actual resources usage and then employ correction mechanisms to dynamically change the resource allocation among users. It also allows the end systems to adjust their resource reservation according to the network resource availability and their requirements. Furthermore, we also revise the current multicast routing protocol to reduce the resource reservation failure rate. Our multicast routing algorithm attempts to find a multicast distribution tree with QoS constraints. As many receivers as possible will share the multicast paths. It can remedy two problems caused by current design of RSVP. One is the avoidance of choosing those data paths whose available resource is insufficient. The other is to solve the heterogeneity problem caused by different network elements.