PariSync: Clock synchronization in P2P networks

This paper presents PariSync, a distributed system for clock synchronization in DHT-based peer to peer networks. PariSync is formed by two modules: a topology module, that chooses for each node a small subset of neighbors with which to exchange timing information (piggybacking on the DHT link structure) and an extimation module, that assembles the information into an extimate of the node´s offset and drift from a global virtual clock emerging from the consensus of all peers. PariSync works on extremely large peer-to-peer networks (millions of nodes) exhibiting good performance even in the presence of churn and malicious nodes. We provide a version of PariSync in pure Java and in JXTA.