Upon receipt of a document request, a client assistant examines its cache
for the document. If not successful, a server searches for the requested
document in its cache. If the server copy is still not fresh or not
found, the server seeks the document from its host. If the host cannot
provide the copy, the server seeks it from a document repository. Certain
documents are identified from the document repository as being fresh or
stable. Information about each these identified documents is transmitted
to the server which inserts entries into an index if the index does not
already contain an entry for the document. If and when this particular
document is requested, the document will not be present in the server,
however the server will contain an entry directing the server to obtain
the document from the document repository rather than the document's web
host.