Multicast congestion control and loss recovery with network assistance
Biplab Sikdar, Jun Peng · 2004
Internet Protocol (IP) multicast is probably the most efficient data delivery method for one-to-many and many-to-many communications on the Internet. Basically, it avoids duplicate datagrams on the same link by coping datagrams at the forks where they need to go different ways to reach different receivers. The IP multicast architecture consists of several essential elements including group management protocols, routing protocols, and transport protocols. Group management protocols are used by receivers and routers to communicate membership information, while routing protocols are responsible for building and maintaining a multicasting structure to achieve efficient data delivery in a multicast session. Transport protocols usually deal with congestion control and loss recovery in data delivery. This thesis focuses on congestion control and loss recovery for IP multicast. Many challenges exist for designing a transport protocol for IP multicast. The challenges stem from the two important functionalities of a full transport protocol: congestion control and loss recovery. For congestion control, the heterogeneity of paths and receivers in a typical multicast session pose big challenges in achieving fairness among receivers in the same session and between competing sessions. In general, layered multicast is a practical choice for dealing the heterogeneity in multicast. The most important requirements of layered multicast congestion control are effective and efficient layer adjustment and fairness with other competing flows (basically, TCP or TCP-like flows). Meanwhile, high efficiency and scalability in multicast loss recovery demands good request suppression, local recovery, and re-transmission scoping. End-to-end congestion control and loss recovery schemes, in general, cannot fully handle these challenges in multicast, while existing network-assisted schemes either depend on significantly revised network structures or still have low performance in some major aspects. In this thesis, we propose the use of minimum network assistance to address the challenges posed by congestion control and loss recovery in multicast. For congestion control, we propose the routing-based on-site congestion control. This approach not only achieves effectiveness and efficiency in congestion control but also fairness among competing flows. Meanwhile, it is suitable for wireless environments, such as satellite networks and mobile ad hoc networks. For loss recovery, we propose the on-demand construction and maintenance of minimum loss recovery structure for a loss site and active injection of repair packets into the loss region. This active and on-demand approach is very efficient, and it also achieves high performance in request suppression, local recovery, and retransmission scoping. In addition, the approach has low recovery latency.