Optimal Bandwidth Allocation in mesh-based Peer-to-Peer Streaming Networks Mar´ ıa Elisa Bertinat, Dar´ ıo Padula, Franco Robledo Amoza, Pablo Rodr´ ıguez-Bocca and Pablo Romero Abstract The design of efficient protocols for mesh-based Peer-to-Peer (P2P) net- works has many challenges, one of them is the bandwidth allocation. On one hand, users (called peers) demand high Quality of Experience and network traffic when they watch their streaming contents. On the other, Internet Service Providers (ISPs) support their business with the capacity of their international links. A recent strat- egy considered in order to meet both peers and ISPs requirements is the Proactive Provider Participation, shortly named P4P [10]. This approach allocates the maxi- mum total traffic in the network, reducing at the same time the percentage use of the most congested links. This paper addresses the bi-level P4P problem. We introduce a polytime solution which achieves any given accuracy when only one content is delivered in the net- work In addition, we design a greedy randomized technique when multiple con- tents are shared. Finally, we apply our algorithm to a real peer-to-peer live video- streaming platform, when a single content is delivered. The results highly outper- form current strategies. 1 Introduction An important amount of today’s Internet traffic is due to live video streaming [2]. For this reason, several peer-to-peer streaming networks were developed in the last years. The most successful ones are PPlive, TVUnetwork, SopCast, with proprietary and unpublished mesh-based protocols [8]. Mesh-based P2P networks are virtual unstructured networks developed at the application layer, over the Internet infras- tructure. Bittorrent is the best known mesh-based P2P protocol, developed for file sharing purposes [3]. The users, called peers, offer their resources(bandwidth in Dar´ ıo Padula Facultad de Ingenier´ ıa, Universidad de la Rep´ ublica, Montevideo, Uruguay e-mail: dpadula@fing.edu.uy 1