Survey on similarity measurement of peers in P2P systems

In P2P systems, peers are often organized by similarity, trying to ensure the content that any peer needs be found in peers who are in short connections with them to improve the efficiency of searching resources which become popular and difficult in P2P field. First, the background of P2P systems and typical applications are introduced. Then the concept of peer similarity and similarity degree are stated as well as current models. After that, a comprehensive induction on similarity measurement of peers is given, and typical methods were summed up. Finally challenges on similarity measurement are discussed and future research trend of similarity measure on peer sets is also summarized.