The termination of the connection is initiated by one person saying the word 'Goodbye' and is confirmed via a like sign from the other person. Computer protocols work in much the same way. The difference is that in the phone system, once a phone connection is established we no longer need to use the phone number during the conversation. Probably the most frequently used protocol, TCP , uses the IP protocol but is itself a connection-oriented protocol. In addition to its IP address every computer on the Internet may have a name called a host name .
Host names are mostly for the convenience of human beings.
They are easier to remember than IP addresses and provide a means of better organizing computers within an organization. Unfortunately, even though a computer may have a host name the IP address is still required to communicate. The translation between host names and IP addresses is done by computers called Domain Name Servers . They act as Internet phone books. The host name is then automatically forwarded to a domain name server which looks up the IP address for that name and sends it back to the computer that requested it.