N~2VOD:A Bilayer Dispatching P2P-VOD Strategy Based On Interest And Location

Different from the traditional C/S which applies the centralized server to manage all the data in the Internet, P2P disseminates tasks, such as uploading, maintenance and management, to each peer in the Internet, which solves bottleneck problem in C/S network. This makes P2P network has received much attention. And the popularity of products related to P2P also sprung up. On the other hand, with the explosion of the Internet multimedia data, more and more scholars and experts started to research how to apply P2P to the transmission of the Internet multimedia data. That is why the P2P streaming media technology has come out.P2P streaming media consists of two fields. One is live-streaming, which is mainly applied on live TV and video conference. The other is the video-on-demand, which is mainly applied on the website of video sharing such as YouTube. As more and more users require to watch multimedia videos at any time and any place, VOD system is getting more and more prevalent. As a result, more and more researchers engage themselves in VOD technology researches.In the P2P streaming media network, peer-to-peer (P2P) distributes the server's load (such as calculation, bandwidth, storage, etc.) to each peer in the Internet. However, due to the diversity of the terminal equipment (such as iPad, smartphones and network TV) which accesses the Internet, and the difference of peers'viewing behaviors (such as interest and VCR, etc.), P2P VOD streaming system is more complicated on management and maintenance compared with live system. Therefore, how to build an effective P2P streaming overlay network has become the major direction of current studying in the field of streaming media. In this paper, we put forward a bilayer transcoding P2P-VOD strategy based on interest and location, and on the basis of this strategy, we proposed a P2P VOD streaming system named N2 VOD system. In this system, peers are divided into two types according to whether they have the multimedia video transcoding functions or not.1) functional peer which has the ability of transcoding; 2) general peer which doesn't have the ability of transcoding. When the peer initially joins the Internet, it neighbors other peers which have the similar interest according to the SS-DA algorithm proposed in this paper, and changes its neighbor with its preference in the later process of watching videos. In the respect of multimedia data transmission between peers, we proposed the FPBA algorithm for the functional peers and the GPBA algorithm for general peers, distributing different bandwidth to different types of end-users. At the same time, taking the diversity of terminal equipment and the difference of location into consideration, the two algorithms give the priority to the peers which have the same type and similar location when selecting their neighbors in the process of data transmission. Hence the transmission efficiency of multimedia has been improved. The simulation results show that, the N2VOD system is able to mitigate the server's load and increase the utilization of peers'bandwidth and storage, thus guarantee the continuous watching videos.