A Content Distribution System based on Sparse Linear Network Coding

Abstract

Abstract — With network coding, intermediate nodes between source and destination node(s) encode the incoming packets into new ones and forward them to their outgoing links. The original content is decoded at the destination node(s). Recent theoretical results show that network coding is beneficial for peer-to-peer(P2P) content distribution. To evaluate the benefit of network coding, we implement a P2P content distribution system based on the sparse linear network coding method. In our system, we use the Chord protocol to construct the system topology. We determine the proper encoding density so as to reach a high probability of generating independent encoded blocks, and to reduce the computational complexity of encoding packets at each peer. To improve the system performance, we use the encoding interval to reduce the probability of transmitting linear dependent packets and dependency test to avoid accepting linear dependent packets possibly from cyclic topology. Lastly, we carry out extensive experiments to show in terms of average downloading time at peers, total distribution time and system throughput, the system with network coding slightly outperforms a BitTorrent-like non-coding system using the local-rarest-first chunk selection policy. I