On the Market Power of Network Coding in P2P Content Distribution Systems

Network coding is emerging as a promising alternative to traditional content distribution approaches in P2P networks. By allowing information mixture in peers, it simplifies the block scheduling problem, resulting in more efficient data delivery. Existing protocols have validated such advantages assuming altruistic and obedient peers. In this paper, we develop an analytical framework that characterizes a coding based P2P content distribution market where peers selfishly seek for individual payoff maximization. Through virtual monetary exchanges, agents in the market buy the coded blocks from others and resell their possessions to those in need. We model such transactions as decentralized strategic bargaining games, and derive the equilibrium prices between arbitrary pairs of agents when the market enters the steady state. We identify the traditional P2P content distribution approach as a special case of network coding, and characterize the relations between coding complexity and market performance metrics, including agents' entry price and expected payoff, thus providing operation guidelines for a real P2P market. Our analysis reveals that the major power of network coding lies in its ability to maintain stability of the market with impatient and selfish agents, and to incentivize agents with lower price and higher payoff, at the cost of reasonable coding complexity.