Deploying a Delivery System

Figure 12.6 shows how all the components connect for delivering content from Contoso Movies Online to the end user through a CDN.

Figure 12.6: The Contoso Movies Online distribution topology, using a CDN.

The production workstations located at Contoso headquarters connect to the corporate LAN, which connects to the Internet through an ISP. The ISP in this case is the hosting service, which is also the CDN. (However, the ISP, hosting service, and CDN could be separate businesses.) Many different scenarios are possible when the Internet is used as the common means of data distribution. The FTP protocol is used to copy (or publish) files to the hosting service, from which point the CDN distributes (or propagates) the content to edge servers throughout the network.

The HTTP protocol is used by the encoder to send a live stream over the Internet to the hosting service. In the Ivanhoe scenario, the encoding computer connects to the Internet over DSL, which could be provided by the same service that provides the ISP, hosting, and CDN services. In other scenarios, the encoded stream could be sent to the Internet over a dial-up connection in, say, Toronto, or over a partial T1 connection in New York. The video signal could also be picked up via satellite at Contoso headquarters, encoded, and delivered live to the host. The Internet provides the common data delivery system for getting content to the host, as well as getting it to the end user.