|
|
HTTP stands for HyperText Transfer Protocol, the protocol used to deliver all resources on the World Wide Web. HTTP defines how the messages are formatted and transmitted.
When a client requests some information (say, clicks on a hyperlink), the browser sends a request message to the HTTP server for the requested objects. The server receives the requests and sends the response message with the objects. However, the HTTP server maintains no information about the clients, and if the client asks for the same object again, the server resends the object. Therefore, HTTP is called a stateless protocol.
HTTP can use both nonpersistent connections and persistent connections. A nonpersistent connection is the one that is closed after the server sends the requested object to the client. In other words, the connection is used exactly for one request and one response.
With persistent connections, the server leaves the TCP connection open after sending responses and hence the subsequent requests and responses between the same client and server can be sent. The server closes the connection only when it is not used for a certain configurable amount of time. With persistent connections, the performance is improved by 20%.
Nonpersistent connections are the default mode for HTTP/1.0 and persistent connections are the default mode for HTTP/1.1.
|
|