Can Network Coding Help in P2P Networks?

In this paper, we compare the maximum achieveable throughput using network coding with routing in P2P networks. Our analysis is based on a simple star network where there is no multicast and network coding can only be applied at the peers. Under the idealized assumption that there is perfect information to realize optimal routing, this model captures the essential elements of a P2P network, yet allows simple analysis for what can be achieved by network coding and by routing respectively. The conclusion is that there is no coding advantage. We then discuss the applicability of this result to a real P2P content distribution system which may operate at lower throughput due to various other factors. Finally, in addition to yielding insights to the present case of P2P networks, we believe this type of non-multicast network models can lead to other new results for network coding in general.