On ISP Friendliness: Introducing an ISP-Friendly Peer-to-Peer Live Streaming System

Abstract: The various capabilities provided by the Internet have attracted a large amount of Internet-based applications over the last decades. Many services that previously only used other means of communication are now also deployed on the Internet. As the content in the communication becomes richer, the bandwidth required to communicate it increases. In the case of delivering audiovisual content over the Internet, a significant amount of bandwidth is required to send the content to a single recipient, and increases rapidly for each additional recipient. To be able to provide scalable, Internet-based systems for video content delivery, researchers and companies have begun to focus on peer-to-peer-based approaches, meaning participants collaborating and contributing their bandwidth to assure content delivery to all others. This thesis proposes a design for a peer-to-peer system for delivery of live video, and provides simulation results for an implementation of the design. The design targets some of the current issues of peer-to-peer systems – mainly that of providing friendliness towards Internet Service Providers (ISPs). Peer-to-peer systems generate considerable amounts of traffic, which is often sent between peers located in different ISPs, even when data is available at a peer in the same ISP as the recipient. This creates problems for ISPs as they often have to pay other ISPs for data sent over cross-ISP connections, and because congestion can occur in the ISPs gateways to the rest of the Internet – the problems increasing with the number of ISPs that the traffic has to go through. This has forced some ISPs to limit or block peer-to-peer traffic completely. The system designed in this thesis uses a gossip-based peer-to-peer protocol for content dissemination, and to minimize cross-ISP traffic, the thesis proposes that peers should choose peers closer in the network topology to connect to. This can be achieved by creating a database composed of ISPs and the distance between them, which is consulted every time a new connection is to be created. The database is small enough to be stored locally at each peer. As long as a peer is able to deliver a clear stream it will only connect to close peers, however should the close peers not be able to provide data at a sufficient rate, the peer will request random peers in the system to also provide it with data. Evaluation of the system in various simulation scenarios shows that it operates well in a constrained environment as well as during peer failures. The evaluation also shows that it is possible to have high clustering of peers and still deliver a clear stream to all of them, as long as a few random connections are allowed to be created when close neighbors can’t provide a suffi cient download rate. Comparing the use of biased neighbor selection to random selection, traffic between ISPs is efficiently reduced in the overall system, the portion of traffic exchanged between peers in the same ISP experience a ten times increase or more in most scenarios, and in larger ISPs that contain many peers, 75% of all traffic is exchanged between peers within the ISP. Thus the design presented in this thesis can be recommended to developers and content providers that are looking to increase ISP friendliness in their existing or future peer-to-peer applications.