QoS-aware hierarchical multicast routing on next-generation internetworks
Several emerging applications of the current and next generation Internet, e.g. IP radio, IP TV, and video and audio conferencing, etc., involve one-to-many and many-to-many data communications called multicasting. Many real-time applications over IP, such as IP Telephony and video conferencing, can not operate with the best effort service provided by current IP networks. To support such applications, IP networks need to provide certain quality of service (QoS) assurances. Most of QoS-based multicast routing protocols are based on a "flat" routing model that do not scale well for large size networks. This thesis proposes QHMRP, a novel QoS-aware hierarchical multicast routing protocol. The scalability issue is addressed by organizing the network as a hierarchy of domains using the full-mesh aggregation technique. The concept of domain 'controller' is used for coordinating the creation and maintenance of multicast trees. The protocol uses a novel reverse flooding approach to connect host routers with the tree while satisfying end-to-end QoS constraints. This is a distributed algorithm, which uses only local state information at each router. The worst-case connection time and message overhead are estimated and analysis shows that QHMRP constructs loop-free multicast trees. Simulation results show that the message overhead of QHMRP is much smaller than that of the flat routing protocol using reverse flooding.