Studies in the implementation of differentiated services networks

Differentiated services model is proposed to provide quality of service to the Internet users while maintaining the scalability of its implementation. Assured forwarding, one of such services, allows users to have assured traffic rate according to their payment with service providers. The current scheme for assured forwarding only supports service payment by sender or receiver exclusively. We extend the framework to control traffic rate in accordance with the payments by sender and receiver. A combined payment by sender and receiver in a complementary manner greatly increases flexibility for the users to access differentiated services networks.; Multicast service is important for many Internet applications. Application layer multicast is proposed as an alternative to IP multicast to avoid the problems that impede IP multicast from taking off. We present a study of the application layer multicast in assured forwarding networks. Our model is based upon previous work on application layer multicast, but with the addition of constraints that models traffic rate requirements and limitations on number of node outputs in assured forwarding networks. The framework is to incrementally construct the multicast tree satisfying the constraints when new members join the multicast group.; Algorithms of low complexity are designed that are suitable for large scale networks; and can be incorporated with the constraints. Known optimal spanning tree algorithms for undirected and directed graphs are also implemented in our incremental network framework. A family of multicast tree construction algorithms are included to provide guidance to network designers in the selection and implementation of an algorithm.