Incorporation of flow and QoS control in multicast routing architectures

Many multicast routing protocols consider only the unicast shortest paths between every pair of source and destination in a group (often based on the number of hops) to setup a multicast tree, such as DVMRP and CBT. Furthermore, they do not offer the ability to consider the resource savings possible in the presence of multiple data flows sharing common paths in a tree, such as CBT and PIM. These aspects hamper resource-efficient routing. In this light, our paper describes flow-based resource allocation control in multicast tree setups. Our proposed model has two aspects: (i) exploring alternate paths to connect a joining user to a tree, should the unicast shortest path not have sufficient bandwidth to sustain the new data flow; and (ii) downstream resource allocation to merge a new data flow with the on-going flows in a tree. (i). Requires 'multi-path connectivity' information at routers in the network, while (ii) requires flow aggregation information to be exchanged between on-tree routers. The model is evaluated by simulation studies. The proposed model can be useful in integrated service networks that contain both low and high bandwidth links, such as future Internet.