Peer-to-Peer (P2P) applications have gained tremendous importance in recent years, as seen through their rapid spreading which began with applications such as Napster, Gnutella, Edonkey, Kazaa and SETI@home. In terms of their traffic volume, these P2P applications have quickly become the most dominant source of traffic on the Internet. According to a study in  in 2003, 50% of the Internet traffic was caused by P2P applications and only 15% by the WWW. Today, this percentage has grown even higher and some experts estimate it to be 80% or more.
P2P is more than just a means for exchanging files. With Skype, Edutella und SETI@home. Currently emerging in application areas other than file sharing, P2P systems take on a communication paradigm different to classical client-server architectures: using cooperation instead of coordination, using decentralization and self-organization in place of centralization, and using incentives instead of controlling.
At the Multimedia Communications Lab, we investigate the following issues of P2P systems:
 N.B. Azzouna and F. Guillemin, Analysis of ADSL Traffic on an IP Backbone Link, in Proceedings of IEEE Globecom 2003, 2003
 Ralf Steinmetz and Klaus Wehrle, Peer-to-Peer-Networking & Computing , Informatik Spektrum, Aktuelles Schlagwort, vol. 27, no.1, pp. 51-54, 2004