What is HTTP in networking?

HTTP stands for Hypertext Transfer Protocol, and is an application layer protocol. HTTP follows the client-server model. It works as follows:

• A client (browser) requests web objects.
• The server sends objects in response.

HTTP defines the message sequence, message structure, and how messages will be exchanged between a client and the server.

Properties and usage

HTTP is stateless, meaning the server does not keep information about past clients. The major advantage of this is that it simplifies the design and ensures privacy.

HTTP works in accordance with the transport layer protocol (TCP) at port 80. The TCP provides reliable data delivery for HTTP exchanges.

HTTP is also connectionless, so there is generally a single TCP connection between the server and the client. The connection terminates after the server sends back a response message.

To sustain a connection, HTTP needs to be updated in the message header.

Message format

HTTP messages include three main parts:

• A request line, which includes what kind of request it is.
• The headers, which provide information about the message.
• The body, which contains the actual content of the message.