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 and randomized block selection, 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 rational agents seek for individual payoff maximization. Unlike existing game theoretical models, we focus on a decentralized resale market-through virtual monetary exchanges, agents 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 further characterize the relations between coding complexity and market properties including agents´ entry price and expected payoff, thus providing guidelines for strategic operations in a real P2P market. Our analysis reveals that the major power of network coding lies in maintaining stability of the market with impatient agents, and incentivizing agents with lower price and higher payoff, at the cost of reasonable coding complexity. Since the traditional P2P content distribution approach is a special case of network coding, our model can be generalized to analyze the equilibrium strategies of rational agents in decentralized resale markets.