Application Layer Multicast Based On Fountain Codes

With the emergence of one to many, many to many applications, multicast technology has become an important direction of research. Application Layer Multicast (ALM) is an alternative of IP layer multicast, multicast function is changed from routers to end-system, which can solve the existing deployment difficulty and poor scalability of IP layer multicast effectively. ALM has been widely deployed in network applications like video conferencing, IPTV, audio and video on demand, Streaming Media and so on.However, with the rising user demand, the shortcomings of stability and reliability with ALM is emerging, hindering the further deployment of the ALM in some way. Fountain codes are rateless erasure filling codes, a kind of application layer Forward Error Correction (FEC) codes which has performance of approaching to the Shannon limit. And it's an effective solution to the feedback storm problem of Automatic Repeat-reQuest (ARQ). Multicast based on fountain code has advantages of scalability and adapt to time-varying channels.This thesis discusses several ALM solutions existed firstly, does some comparative analysis from different angles. Then performance factors which impact multicast quality are analyzed. Besides, AML-related technologies was listed.Next, the thesis selects NICE protocol as the main focus, which is a hierarchical, clustered and implicit method of ALM solution. The research includes the establishment of its hierarchy, the structure of its control topology and data topology, and the management of multicast members. Since the original NICE protocol has not considered the different performance of multicast member, B-NICE protocol considering both of distance and bandwidth is presented..At last, this thesis studies encoding and decoding of fountain codes, then NICE protocol based on fountain codes is presented, the degree distribution of fountain codes and processing between sender and receiver is discussed. The simulation of B-NICE protocol and fountain codes based solution is finished on the network simulation platform OverSim, achieving the aim of reliable transmission of large-scale multicast.