Editorial note

Multimedia delivery over P2P has become a significant research topic over the last decade. Motivated by the ever-increasing need for higher video quality as well as the need for global video access, P2P has become a popular and often used technology for video streaming. P2P techniques not only offer advantages such as robustness, self-organization, and scalability, but they also allow content providers to offer streaming services to a multitude of users with fewer resources. Thus P2P-based video streaming has been an active topic not only in the academic community, but also from a commercial point of view. P2P streaming applications, such as PPLive and UUSee, deliver thousands of video channels to millions of users daily. Moreover, new operating systems and mobile smart phones are starting to ship with support for P2P mechanisms for multimedia delivery, which is the case, for example, with the latest Android operating system. With this supplemental issue of recently submitted TOMCCAP articles related to P2P streaming, we want to accommodate this development. This issue is comprised of six articles which present new approaches for important problems in P2P streaming systems as well as new insights and perspectives in this area.