Streaming multimedia content over the Internet is extremely popular mainly due to emerging applications such as IPTV, YouTube and e-learning. All these applications require simultaneous streaming of multimedia content from one or multiple sources to a large number of users. Such applications impose unique requirements in terms of server bandwidth and playback delay which are difficult to achieve in a scalable fashion with the traditional client-server architecture. Peer-to-peer (P2P) overlays offer a promising approach to support scalable streaming applications, that we broadly refer to as "P2P streaming". Design of a scalable P2P streaming mechanism that accommodates heterogeneity of peers' bandwidth and copes with dynamics of peer participation while ensuring in-time delivery of the multimedia content to individual peers is extremely challenging. Besides these fundamental challenges, P2P streaming applications are facing practical issues such as encouraging peers' contribution and decreasing the costly inter-ISP P2P traffic.

In this dissertation, we study several aspects of live P2P streaming with the goal of improving the performance of such systems. This dissertation can be categorized into two parts as follows. (i) We present the design and evaluation of a mesh-based live P2P streaming mechanism, called PRIME. Further, we perform a head-to-head comparison between the two approaches on live P2P streaming, namely tree-based and mesh-based. We demonstrate the superiority of the mesh-based approach. In the quest for a systematic comparison of existing mesh-based solutions on live P2P streaming, we leverage the insights from our design in PRIME and propose an evaluation methodology. Utilizing the evaluation methodology, we compare the performance of existing mesh-based live P2P streaming solutions. (ii) From a more practical perspective, we tackle some of the existing practical issues in the deployment of live P2P streaming applications, namely providing incentives for participating peers to contribute their resources and designing ISP-friendly live P2P streaming protocols with the ultimate goal of reducing costly inter-ISP traffic. In the end, this dissertation reveals fundamental trade-offs in the design, comparison and meaningful evaluation of basic and practical live P2P streaming mechanisms under realistic settings.