Network-supported congestion control for video multicasting over IP networks

In this thesis, we present our research work in the area of multicast congestion control for video applications. The core work of this thesis is the proposal of the use of a new form of network support to multicast congestion control. Our approach is to bring together simple, loosely-coupled, router mechanisms and adopt them for the multicast case. We use a variant of the Explicit Congestion Notification (ECN) mechanism to notify the sender of a multicast session of potential network congestion. We develop an end-to-end multicast system using this congestion control scheme. This included the development and tuning of an elaborate rate adaptation algorithm that operates at the sender. We build this system on top of a network that applies packet priority-dropping to insure providing minimum video quality during persistent congestion. In particular, the work is targeted at the IETF Assured Forwarding (AF) services networks. We show that the synergy of these mechanisms deals with the heterogeneity of receivers in a scalable manner and avoids the major problems of earlier approaches. We believe that this work is of great value to multicasting applications in future QoS-aware networks.