Abstract. Recent growth of the multimedia content delivery over the Internet and the popularity of the peer-to-peer (P2P) architecture have opened new horizons for emerging novel services over the Internet. Currently, most of multimedia services are being offered to the end users by using set-top boxes installation on the client’s premises, with integrated media storage capabilities and their adaptation. The organization of the end-clients in P2P fashion has great potential to change business models to offer new value-added multimedia services and therefore to generate substantial revenue for service providers. In this paper, we present a mechanism to organize the sender peers in hierarchical hybrid overlay networks. The objective of such organization is to facilitate the receiver peer (content consumer) to select best sender peers for the provision of better QoS (Quality of Service). To construct the hybrid overlay networks, peers offering the same video quality are placed together at the same level of overlay networks. The organization of sender peers within these overlays is subject to (1) the semantic of the video provided by the peer (base layer, or enhancement layers) and (2) the QoS offered by each peer along the end-to-end path. The proposed streaming mechanism is receiver-centric where receiver peer selects a number of sender peers from the overlay networks to receive media contents. The performance evaluation performed using ns-2 simulator shows that hybrid overlays organization mechanism is helpful to enhance the overall QoS by significant improvement in received video packets throughput, the packets drop ratio and transmission delay. 1

Structured peer-to-peer systems can be organized hierarchically as two-level overlay networks. The top-level overlay consists of groups of nodes, where each group is identified by a group identifier. In each group, one or more nodes are designated as supernodes and act as gateways to the nodes at the second level. A collision occurs during join operations, when two or more groups with the same group identifier are created at the top-level overlay. Collisions increase the lookup path length and the stabilization overhead, and reduce the scalability of hierarchical peer-to-peer systems. We propose a new scheme to detect and resolve collisions, and we study the impact of the collision problem on the performance of peer-to-peer systems. Our simulation results show the effectiveness of our scheme in reducing collisions and maintaining the size of the top-level overlay close to the ideal size.

Soutenue le JJ/mois/2008 devant le Jury composé de: