Minimizing weighted sum delay for one-to-many file transfer in peer-to-peer networks

This paper considers the problem of transferring a file from one source node to multiple receivers in a peer-to-peer (P2P) network. The objective is to minimize the weighted sum delay (WSD) for the one-to-many file transfer where peers have both uplink and downlink bandwidth constraints specified. The static scenario is a file-transfer scheme in which the network resource allocation remains static until all receivers finish downloading. This paper shows that the static scenario can be optimized in polynomial time by convex optimization, and the associated optimal static WSD can be achieved by linear network coding. This paper also proposes a static rateless-codingbased scheme which has almost-optimal empirical performance. The dynamic scenario is a file-transfer scheme which can re-allocate the network resource during the file transfer. This paper proposes a dynamic rateless-coding-based scheme, which provides significantly smaller WSD than the optimal static scheme does.