Peer - to -Peer

Peer-to-peer (P2P) systems have become a popular medium to share huge amounts of data. P2P systems distribute the main costs of sharing data - disk space for storing files and bandwidth for transferring them - across the peers in the network, thus enabling applications to scale without the need for powerful, expensive servers. Their ability to build a resource-rich system by aggregating resources enables them to dwarf the capabilities of many centralized systems for little cost.
There are, however, important challenges that must be overcome before the full potential of P2P systems can be realized. For example, the scale of the network and the autonomy of nodes make it difficult to identify, model and distribute resources that are available. Furthermore, some nodes may be malicious which makes it difficult to provide peers with authentic information or prevent denial-of-service attacks. These issues, and others, have motivated our research on understanding and improving P2P systems.