| 摘要 |
A method of and apparatus for accelerating data retrieval on a widely dispersed content distribution network such as the World Wide Web. The system associates a concept URI with a resource which can then serve as a reference for a group of resources. When the system receives a request from a client calling for a resource in this group, it prepares a delta encoded responses based on the difference between the reference document and the response it has obtained from an origin server (the identity response). The system then sends the client the delta encoded response, an identification of the reference document used to prepare the delta encoded response, and an address where the reference document may be obtained if a client does not already have a copy. A client either decodes the information from the system by reconstituting the response using the delta encoded response and the reference if it already has a local copy, or, if it does not already have a local copy, using the address to retrieve a local copy and then carrying out the decoding. The selection of a reference is based on heuristics. The system also has the capability of changing which resource it will use as a reference based on the performance of the reference, i.e., whether the reference has continued to produce acceptably small deltas. The reference may be a version of an actual resource, or created by the system to serve the group of resources as a reference. |
