Broadcast Scheduling for a P2P Spanning Tree

In peer-to-peer (P2P) networking, broadcast is required for many operations. For structured P2P networks, Ji Li et al. proposed to build a broadcast spanning tree so that each non-leaf peer forwards broadcast messages to its children along the tree. When peers are uniformly distributed, it is highly expected that a broadcast message will reach all peers by at most O(log N) hops, where TV is the network size. We study DHT-based P2P broadcast in finer time granularity. In a round, an activated peer - that has received the broadcast message - can send the message to a non-activated peer. In this paper, we present a fully-distributed algorithm to schedule the message forwardings of a non-leaf peer in a spanning tree. We use a bottom-up approach: each non-activated peer finds an activated peer along the path from its parent to the root. Simulation results show that the time required for broadcast is significantly reduced.