The browser establishes a TCP connection to the Web cache and sends an HTTP request
for the object to the Web cache. The Web cache checks to see if it has a copy of the object
stored logically. If it does, the Web cache forwards the object within an HTTP response
message to the client browser.

If the Web cache does not have the object, the Web cache opens a TCP connection to the
origin server, that is, to www.someschool.edu . The Web cache then sends and HTTP
request for the object into the TCP connection. After receiving this request, the origin
server sends the object within an HTTP response to the Web cache. When the Web cache
receives the object it stores a copy in its local storage and forwards a copy within an HTTP
response message, to the client browser.

Note that the cache is both a server and a client at the same time. When it receives requests
form and sends responses to a browser, it is a server. When it sends requests to and receives
responses from an origin server, it is a client. A Web cache is purchased and installed by an
ISP. Web caching has seen deployment in the Internet for two reasons: it can substantially
reduce the response time for a client request and it can reduce traffic in the Internet as a
whole, thereby improving performance for all applications.