The apparent speed of a connection between a browser at a user station and a
proxy or gateway on a network such as the Internet is increased by providing a
local proxy at the user station which interacts with a remote proxy. While the
remote proxy is retrieving a newly requested World Wide Web page, for example,
from the appropriate content provider, it may also be sending to the local proxy
a stale cached version of that page. When the new version of the page is finally
retrieved, the remote proxy determines the differences between the new version
and the stale version, and, assuming the differences do not exceed the new page
in size, sends the differences to the local proxy which then reconstructs the new
page from the differences and the stale version. The local proxy delivers the new
page to the browser, which need not even be aware that a local proxy exists; it
is aware only that it received the page it requested. Because computational speed
and power are frequently higher and cheaper than transmission speed, the apparent
speed of the connection between the user station and the network has been increased
at modest cost.
