To the Web pages you user, the proxy server is invisible; all Internet requests and returned responses appear to be directly with the addressed Internet server. (The proxy is not quite invisible; its IP address has to be specified as a configuration option to the browser or other protocol program).
An ADVANTAGE of a proxy server is that its cache can serve all users. If one or more Internet sites are frequently requested, these are likely to be in the proxy’s cache, which will improve user response time. In fact, there are special servers called cache servers. A proxy can also do logging.
GATEWAY cache is also a shared cache (sometimes referred to as reverse proxy caches, surrogate caches, or even HTTP accelerators) but on the server side. Installed by network administrators, it makes websites more scalable, reliable and performant.