Introduction:Peer-to-peer (P2P) is a network structure that replaces the conventional client-server architecture. P2P networks use a decentralized model where each system acts as a peer and serves as a client with its own level of server functionality. Meanwhile, a partner plays the role of client and server. That is, the node can send calls to other nodes and at the same time answer incoming calls from other nodes in the system. It is different from the traditional client-server model where a client can simply send requests to a server and then wait for the server's response. In a client-server network, server capacity will decrease as the amount of clients requesting services from the server increases. Despite this, in P2P systems the overall network performance improves significantly as an increasing number of nodes are added to the system. These companions can organize themselves into groups with specific purposes (ad hoc) as they communicate, work together, and offer data transfer capabilities with one another to complete the current workload (file sharing). Each companion can transfer and download at the same time, and in a procedure like this, new companions can join the group while old companions leave at any time. This active reassociation of peer group members is not opaque to the end consumer. Another characteristic of a P2P network is its fault-tolerant ability. The moment a partner stops working or detaches from the system, the P2P process will continue using the remaining partners. For example, in a Bit Torrent system, all users who download a certain document also act as a server. The moment a user discovers that one of the associates is not reacting... middle of paper... of domestic customers, care must be taken to avoid any possible spread of viruses on the peer to peer system (Cornelli, 2002). References:1. B.F. Cooper and H. Garcia-Molina. “Self-monitoring peer-to-peer research networks”. Technical Report, Department of Computer Science, Stanford University, 2003.2. B.F. Cooper and H. Garcia-Molina. SIL: Modeling and measuring scalable peer-to-peer research networks. Technical Report, Department of Computer Science, Stanford University, 2003.3. F. Cornelli, S. De Capitani Di Vimercati, S. Paraboschi and S. Samarati. Choosing reliable servers in a P2P network. In Proceedings of the Eleventh World Wide Web Conference, May 2002.4. A. Crespo and H. Garcia-Molina. Routing indices for peer-to-peer systems. In the Proc. of the 28th International Conference on Distributed Computing Systems, July 2002.