Streaming Media White Paper 2008 - (Page 21) www.streamingmedia.com 21 Improving Your Streaming Setup with Pi-CAST Pi-CAST is the latest in cutting-edge digital streaming solutions. By using the principles of distributed computing, Pi-CAST can enhance the quality of the user experience while, at the same time, lowering the overall bandwidth cost of the stream. Yes, it’s better, and it’s cheaper. Pi-CAST technology works best with websites and applications that have high streaming traffic—either live or on demand— for video, audio, or data streams: • Live event streaming—team sports events, prize fights, concerts, speeches, awards shows, distance learning • On-demand streaming—TV shows, movies, movie trailers, video clips, video archives, file downloads bandwidth loads and is incredible in scaling up to meet demand (just look at the popularity and proliferation of P2P piracy), it lacks the reliability of a central server model. How Does Pi-CAST Work? Pi-CAST attempts to realize the benefits of both a central server/CDN model and a decentralized P2P network model.The solution starts with an existing CDN, so as to retain the stability, security, and control of the centralized infrastructure. However, once there are more than two simultaneous viewers, Pi-CAST begins to coordinate sourcing between individual concurrent users, creating an ad hoc P2P network infrastructure. Each viewer is enabled as a peer and acts as an additional source to the stream. The Pi-CAST Broker indexes and coordinates between the CDN and all available peers in this distributed peer-cast environment. This CDN/P2P hybrid framework is at the heart of Pi-CAST and is what allows for its greater efficiency,easy scalability,higher quality, and lower costs while not sacrificing stability, security, or controllability.The CDN is never cut out; it is always there as a quality of service. By taking advantage of both the upstream and downstream bandwidth of each individual peer, Pi-CAST is able to boast of increased quality (high definition for video up to 6.5Mbps) and lower bandwidth costs. The streams or stream portions that are sourced by peers are the load that is taken off the CDN; in other words, it’s money saved. Furthermore, the higher the demand and concurrent users, the better the P2P environment. Lower Cost Bandwidth costs associated with video streaming are a linear function of the number of consumers and file size. Increase the number of consumers and costs go up. Increase the quality or video length (file size) and costs go up. Every bit of every file that is streamed to every user is paid for by the content owner.By distributing the bandwidth load to multiple peers and using the upstream and downstream bandwidth of each peer, Pi-CAST offsets the overall bandwidth burden from the CDN, resulting in dramatically reduced bandwidth costs. Current Streaming Models Most streaming today comes out of a central server model supplied in large scale by content delivery networks (CDNs). When an individual wants to view a video, he or she sends a request upstream to the central server, which coordinates and supplies the video downstream for all incoming demand.This is a tested, tried, and true model that works; it is stable, secure, and extremely controllable. The only problem is that it’s expensive, especially when scaling to meet demand. The content owner has to cover the cost of bandwidth and pay the CDN for every bit of data transferred downstream to the viewing computer. Peer-to-peer (P2P) streaming is an alternative that does not suffer from the drawbacks of costly bandwidth or scalability. In a decentralized P2P network model, each individual viewer also acts as a coordinator and supplier. A user viewing the video will be sourcing that same video at the same time, coordinating with hundreds of other peers. The result is a much more efficient use of individual resources; both upstream and downstream are fully utilized. While a P2P network model may efficiently distribute Central Server Stream. The Central Server coordinates and supplies the stream for each individual computer. Downstream bandwidth gets the stream from the server to the requesting computers. Benefits are security, stability, and control. http://www.streamingmedia.com
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