  Recent years mesh-based Peer-to-Peer live streaming has become a promising
way for service providers to offer high-quality live video streaming service to
Internet users. In this paper, we make a detailed study on modeling and
performance analysis of the pull-based P2P streaming systems. We establish the
analytical framework for the pull-based streaming schemes in P2P network, give
accurate models of the chunk selection and peer selection strategies, and
organize them into three categories, i.e., the chunk first scheme, the peer
first scheme and the epidemic scheme. Through numerical performance evaluation,
the impacts of some important parameters, such as size of neighbor set, reply
number, buffer size and so on are investigated. For the peer first and chunk
first scheme, we show that the pull-based schemes do not perform as well as the
push-based schemes when peers are limited to reply only one request in each
time slot. When the reply number increases, the pull-based streaming schemes
will reach close to optimal playout probability. As to the pull-based epidemic
scheme, we find it has unexpected poor performance, which is significantly
different from the push-based epidemic scheme. Therefore we propose a simple,
efficient and easily deployed push-pull scheme which can significantly improve
the playout probability.
