Research Of Tree-Based Many-to-Many Reliable Multicast

Nowadays, the Internet technologies are developing forward rapidly. While, as an efficient technology to improve the bandwidth utilization, multicast is relatively tardy. With the increasing expansion of information, demand for large scale and high efficient data transmission is difficult to be met. The current technologies can't guarantee the balance of performance. They often appear to be excessive bandwidth cost.For the advantage of saving network bandwidth, multicast technologies had been developed rapidly in the last two decades. A lot of reliable multicast model had been presented according to different applications. As a subject of the ECGIN(EU-China Grid Inter-Networking) project which is funded by the Information Technology Research Program in the Sixth Framework of EU Technology Development, we finish the research and development of reliable multicast, which is a grid middleware module.Reliable multicast is based on IP multicast, it provides reliability for IP multicast communication. Reliable multicast can be layered structure, cloud-like structure or the hierarchical tree structure. The hierarchical tree structure is proved to have better performance in the reliable multicast protocols. This advantage make the tree-based reliable multicast protocol be more suitable for large scale and high efficient data transmission in grid network.However, the tree structure is difficult to satisfy multiple senders in reliable multicast session. In this paper, we discuss the current technologies of reliable multicast comparatively. Then a many-to-many reliable multicast mechanism with the corresponding congestion control model and error control model is proposed. The congestion control model introduces a congestion prediction mechanism which can be used to avoid congestion condition of the multicast transmission. For the error control model, we combine the ARQ (Automatic Repeat-reQuest) and FEC (Forward Error Correction) mechanism. Lastly, we realize the proposed many-to-many reliable multicast mechanism by programming on TRAM (Tree-based ACK Reliable Multicast) which is a tree-based one-to-many reliable multicast protocol. The test results show that the proposed many-to-many reliable multicast mechanism has lower retransmission rate and less congestion compared with TRAM in the same condition without change the reliability and throughput.