One-way Broadcast Networks Reliable Multicast Technology Research

Multicast is an effective way to send one copy of data to multiple client. With its high bandwidth utilization and low host workload, multicast is getting more widely used than ever especially in group-based commercial and military communication systems. However, there exists two limitations on these applications: the first, current IP networks are typically non-broadcast ones, which disable multicast applications of large-scale kind; the second, UDP(or even raw IP) often serves as multicast traffic carrier, and with only their best effort service, reliable transportation can't be assured.This article try to prompt a new scheme to tackles these problems, and implements a reliable file multicasting system on DVB (Digital Video Broadcasting) network. This system consists of two main parts, the file layer and transport layer, which cooperate to transfer file to multiple receivers. This system is feed-back free. This feature is unique and enables its use on unidirectional links where there is no (or a very limited one) back channel. This is also the reason why system scalability is unlimited, making it a good solution for very large scale content distribution.This article begins with an introduction of reliable multicast. Then several techniques are described which are designed to modify the general scheme according to the characteristics of the system. At last, we show the implementation of the system and present the summary.