ABSTRACT
In recent years, peer-to-peer (hereafter P2P) networks and systems have attracted increasing attention from both the academy and industry. P2P systems are distributed systems that operate without centralized global control in the form of a global registry, global services, global resource management, global schema or data repository. In the P2P model, all participant nodes (i.e, peers) have identical responsibilities and are organized into an overlay network which is a virtual topology created on top of - and independently from - the underlying physical (typically IP) network. Each peer takes both the role of client and server. As a client, it can consume resources offered from other peers, and as a server it can provide its services for others.
