Hypertext Transfer Protocol (HTTP)

• The hypertext transfer protocol (HTTP) was developed by Tim Berners-Lee in 1991

• HTTP was designed to transfer pages between machines

• The client (or Web browser) makes a request for a given page and the Server is responsible for finding it and returning it to the client

• The browser connects and requests a page from the server

• The server reads the page from the file system, sends it to the client and terminates the connection.

Electronic Mail Protocols:

• Electronic mail uses the client/server model

• The organisation has an email server devoted to handling email

o Stores and forwards email messages

• Individuals use email client software to read and send email

o (e.g. Microsoft Outlook, or Netscape Messenger)

• Simple Mail Transfer Protocol (SMTP)

o Specifies format of mail messages

• Post Office Protocol (POP) tells the email server to:

o Send mail to the user’s computer and delete it from the server

o Send mail to the user’s computer and do not delete it from the server

o Ask whether new mail has arrived.