What is DHT-Based Message Routing

Since the deployment of IP multicast remains restricted due to many practical and political issues, researchers have shifted focus to exploiting application-layer multicast for multicast data delivery. Recently there has been considerable interest in applying DHT routing algorithms to application-level multicast. However, early DHT-based multicast protocols are insufficient in addressing a number of technical issues such as heterogeneous capacity of nodes or node churn. In this chapter, the author describes a solution called BAM-Chord (i.e., Bandwidth Adaptive Multicast over Chord) that optimizes the topology of a multicast tree based on node bandwidth. In the proposed solution, node position (i.e., node identifier) on a BAM-Chord ring will be decided based on node bandwidth capacity such that it can build a wide and balanced multicast tree rooted at the source node. As a result, BAM-Chord protocol can utilize network resources of every node to reduce the depth of the multicast tree and take advantages of DHTs in maintaining the multicast tree.