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HTTP and TCP/IP

Each time a HTTP request is sent, a TCP/IP connection is made. When a browser makes a request, the following network activity results:

1. The browser initiates a TCP/IP connection to the web server on the host and port identified in the URL of the request.

2. The host sends back a TCP acknowledgment to indicate a virtual circuit has successfully been established.

3. The browser sends the HTTP request in full to the server using the established connection.

4. The server acknowledges the receipt of the request and starts to generate a response. The browser waits for the response and times out if the response doesn't arrive within a preset time limit.

5. The server sends the HTTP response message to the browser.

6. The browser acknowledges the receipt of the complete HTTP response.

7. The server disconnects the virtual circuit.

Each HTTP request-response sequence is a completely separate network connection: each request message sent by a web browser-or any other HTTP user agent-is totally independent of any other request. Every request message a web server receives has its own separate response. This independence of requests is what makes the HTTP protocol stateless.

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