I. Introduction
Peer-to-peer systems for live streaming, such as TVAnts and Sopcast, have recently met considerable success. As testimony for this, PPLive, which enjoys over 100 million users, has obtained in 2008 a license from the Chinese government to broadcast media content. Despite this growth and evolution to mainstream usage (as opposed to underground, illegal usage), peer-to-peer systems have recently been facing strong criticisms from ISPs.