If a request is received for content that is not stored, a terrestrial line is used one time to transmit the Web page to the secondary cache. After this initial request, the content remains stored in the secondary cache for immediate availability. Three Key Strategies Such a system relies on a combination of intelligent caching, multicast transmission and content management strategies to provide a fast, reliable path from one edge of the network to another. Intelligent controls reside in the primary and secondary caches and are essential to sharing limited satellite bandwidth across many users. Use of secondary caches minimizes the delay when content is requested, while the primary caches eliminate the need to burden the content providers' server with requests, thus saving bandwidth for content publishers.
Multicast transmission is key to making the dual-edge distribution model successful.
Multicast can also be used to deliver push channels and real-time content such as streaming media. Finally, content management allows automated monitoring of content stored in the primary and secondary caches, URL hit statistics, and channel and subscription information. Likewise, content management tools offer service providers greater control over the distribution system. Service providers can subscribe to the channels made available by the primary caches, block certain URLs from being pushed into the secondary Web cache, or configure system operational parameters. Ensuring Quality and Value With any content distribution system, it is imperative to ensure the quality of the transmission and service.