Ranking factors in peer-to-peer overlay networks

Abstract

A large number of peer processes are distributed in a peer-to-peer (P2P) overlay network. It is difficult, maybe impossible for a peer to perceive the membership and location of every resource object due to the scalability and openness of a P2P network. In this article, we discuss a fully distributed P2P system where there is no centralized controller. Each peer has to obtain service information from its acquaintance peers and also send its service information to the acquaintance peers. An acquaintance peer of a peer p is a peer about whose service the peer p knows and with which the peer p can directly communicate in an overlay network. Some acquaintance peer might hold obsolete service information and might be faulty. Each peer has to find a more trustworthy one among acquaintance peers. There are many discussions on how to detect peers that hold a target object. However, a peer cannot manipulate an object without being granted access rights (permissions). In addition to detecting what peers hold a target object, we have to find peers granted access rights to manipulate the target object. The trustworthiness of each acquaintance is defined in terms of the satisfiability and ranking factor in this article. The satisfiability of an acquaintance peer shows how much each peer can trust the acquaintance peer through direct communication to not only detect target objects but also obtain their access rights. On the other hand, the ranking factor of an acquaintance peer indicates how much the acquaintance peer is trusted only by trustworthy acquaintance peers which is different from the traditional reputation concept. We evaluate how the trustworthiness of an acquaintance peer is changed through interactions among peers in a detection algorithm.