Live Video and IP-TV

P2P architectures designed for video broadcasting have in the very last years gained a prominent role. This Chapter aims at providing a comprehensive insight of the most recent advances in the field, focusing on live video streaming. The first part of the Chapter puts forth a classification of P2P video solutions, adoptingalternative sorting criteria that hide different design approaches. It then concentrates on the conceptually attractive issue of data diffusion process within the P2P overlay.An overview of the most interesting P2P IP-TV systems currently available over the Internet is also provided, and the most salient features they exhibit highlighted.Next, the definition of the quality of experience (QoE) for a system user, as well as the recording of the whole system performance via local and centralized measurementapproaches, is commented upon. The second part of the Chapter completes the view, bringing up the modeling efforts that capture the main characteristics and limits of a P2P streaming system, both analytically and numerically. The Chapteris closed by a pristine look at some challenging, open questions: the issue of peers that lie behind NAT and firewalls is discussed; the benefits and the limits of crosslayer design are commented, with a specific emphasis onto the adoption of advancedcoding techniques.