The World Wide Web (“web”) uses the client-server model to communicate information between clients and servers. Web servers are coupled to the Internet and respond to document requests from web clients. Web clients (e.g., web “browsers” are programs that allow a user to simply access web documents located on web servers.
An example of a client-server system interconnected through the Internet may include a remote server system interconnected through the Internet to a client system. The client system may include conventional components such as a processor, a memory (e.g., RAM), a bus which coupled the processor and memory, a mass storage device (e.g., a magnetic hard disk or an optical storage disk) coupled to the processor and memory through an I/O controller and a network interface, such as a conventional modem. The server system also may include conventional components such as a processor, memory (e.g., RAM), a bus which coupled the processor and memory, a mass storage device (e.g., a magnetic or optical disk) coupled to the processor and memory through an I/O controller and a network interface, such as a conventional modem.
To define the addresses of resources on the Internet, Uniform Resource Locator (URL) system are used. A URL is a descriptor that specifically defines a type of Internet resource and its location. To access an initial web document, the user enters the URL for a web document into a web browser program. Then, a request is made by a client system, such as a router or other network device, and is sent out over the network to a web server. Thus, the web browser sends a request to the server that has the web document using the URL. The web server responds to the request and sends the desired content back over the network to the requester. For example, the web server responds to the HyperText Transfer Protocol (HTTP) request by sending the requested object to the client. In many cases, the object is a plain text (ASCII) document containing text (in ASCII) that is written in HyperText Markup Language (HTML); however, the object may be a video clip, movie or other bandwidth intensive content.
A problem with the Internet is that it has limited bandwidth resources and different points in the Internet may experience network congestion, resulting in poor performance especially for bandwidth-intensive applications. The Internet backbone is often painfully slow. The bandwidth limitation is mainly due to one or more congested links between the web server and the client. Broadband access can help in solving the first mile problem but does not help if the congestion occurs deeper in the network. The “first-mile” is the first link from the server to the Internet. This can become a bottleneck if the content provider does not provision for sufficient bandwidth on this link or if there is a “flash-flood” of requests to the server.
One prior art solution to accommodate the slowness of the Internet backbone is to move content closer to individuals desiring the content. To that end, content may be cached on the carrier edge and requests for such content may be serviced from these caches, instead of the web server servicing the requests. Distributing content in this manner can require large numbers of cache memories being deployed at the carrier edge and each cache memory stores content from a number of sites. When a request is made for content from a site that has been stored in one (or more) of the cache memories that is closer (from a network proximity viewpoint) to the requester than the original website, the request is satisfied from the cache. In such a situation, the interactive experience for text and images is improved significantly only if content from the site has been stored in the cache and the individual making the request is close enough to one of the servers supporting such a cache to satisfy requests with the content stored therein. This is referred to as carrier edge caching. One provider of such a service is Akamai. Also, such an arrangement for caching content requires that the content owner and the entity caching the content enter an agreement with respect to the access for that content so that the content can be stored ahead of time. Some of the providers of a carrier edge caching service use dedicated links (e.g., via satellites) to feed web pages and embedded objects to these servers and circumvent the Internet backbone entirely. Providing carrier edge caching for high resolution video requires a particularly large number of servers to be deployed, since the number of clients each server can handle simultaneously is very small.
While carrier edge caching takes the load off the backbone and has the potential to significantly improve the end user's experience for text and image-based content, there are two major shortcomings with this approach. First, it requires hardware infrastructure to be deployed on a giant scale. Without servers in all major ISP's point of presence (POPs) and satellite receivers in central offices (COs), caching on the carrier edge does not work effectively. To deploy and maintain this hardware infrastructure is very cost intensive. Second, the last mile access link remains the bottleneck for affordable truly high resolution video for the foreseeable future.
While carrier edge caching has shortcomings, there are other problems associated with providing content over the Internet. For example, when providing content over the Internet, a content provider is limited in only being able to display the content in one way and without any insight into what content is already cached at a particular client. In other words, the content provider is limited in that it does not know what client side caching is occurring. This may limit a content provider's ability to control the number and order in which those content objects are displayed as that is under the control of the browser. This is of significance when the content provider only desires to allow display of content to which an individual has subscribed.
Another limitation on the content provider is that they cannot provide different sets of content objects to match different clients having different resources. In other words, a content provider cannot determine the resources that a client requesting content has before sending content objects to the client to tailor the set of content object for the particular client. This causes the content provider to provide the same set of content objects to all clients where the content objects are selected based on the likelihood that the majority of clients will be able to display the content objects, which is not near optimal.