Open Issues in P2P Multimedia Streaming

Peer to Peer networks (P2P) consist of a set of logically connected end-clients called peers, which form an application-level overlay network on top of the physical network. P2P solution facilitates contents/files sharing among Internet users in a fully distributed fashion. This paradigm is anticipated to resolve observed limitations in current centralized solution distribution and to significantly improve their performance. P2P networks are undergoing rapid progress and inspiring numerous developments. Although initially P2P networks were designed for file sharing, but their dynamic nature makes them challenging for media applications streaming. Despite recent advances in streaming P2P multimedia system, many research challenges remain to be tackled. This paper presents a state of the art study on several solutions, which exploit the power of P2P technique to improve the current multimedia streaming protocol. Different aspects related to the topic are explored in order to point out the open research issues in the domain of Peer to Peer Multimedia Streaming. Our foremost objective in this paper is to motivate and guide the ongoing research to tackle these challenging problems and help to realize efficient streaming multimedia P2P mechanisms. Concurrently, we observed the extreme popularity of P2P networks during last few years. They are autonomous and distributed systems that aggregate a large amount of heterogeneous nodes known as Peers. These peers incorporate with each other to accomplish some tasks/objectives. Such a system encompasses interesting characteristics like self configuration, self adaptation and self organization. P2P phenomenon offers several facilities. It allows information flow exchange from and back to end user, rapid and dynamic set up of communities sharing the same interests. The main targets of such systems are file sharing applications like Kazaa (15), eDonkey (16), BitTorrent (17)… These intrinsic characteristics make the peer-to-peer (P2P) model a potential candidate to solve the pointed out problem in multimedia streaming over the Internet. P2P networks overcome the setback of bottleneck around centralized server due to its distributed design and architecture. Moreover, it facilitates to manage dynamically the available resources in the networks since they scale with the number of peers in the systems. Although, P2P technology gives novel opportunities to define an efficient multimedia streaming application but at the same time, it brings a set of technical challenges and issues due to its dynamic and heterogeneous nature. Even though the problem has been already studied in the literature (11,12,13,14), works on P2P media streaming systems is still in the early stages, and for a P2P streaming to be enhanced, important research efforts and investigations are still required. Existing P2P protocols must be revised or re-invented and other specific problem need to be addressed to meet the multimedia streaming requirement. Our objective in this article is two fold, firstly to provide a better understanding of the basic concepts of multimedia streaming over P2P networks, and secondly to identify research challenges related to this area. The rest of this article is organized as follows: P2P streaming network architecture is described in section II, a comparison for different video coding techniques in the context of P2P streaming is illustrated in section III, some existing solutions for the P2P media streaming are presented in section IV, we highlight certain issues for the domain in section V and paper is summed up by making some concluding remarks in section VI.