Abstract: Based on the graph theory and finite field operation, this paper introduces the principle of network coding and its applications. For a decentralized content distribution network, three coding mechanisms including uncoded distribution, erasure coding based distribution and network coding based distribution are discussed. The excellent performance of network coding based content distribution is demonstrated with both theoretic analysis and computer simulation experiments. Key issues in practical network coding are presented.

Key words: content distribution, multicast
, P2P, network coding