Interconnected Networks and Communication

• The Internet is essentially a network of networks and its success depends upon “cooperation”.
• Cooperation among the networks and computers that compose the Internet is paramount.
• This cooperation is accomplished by a common set of protocols.
• The protocol that determines how computers connect, send and receive information on the internet is Transmission Control Protocol/Internet Protocol (TCP/IP).
• In facts, TCP/IP consists of about 100 different protocols and new ones are developed and added regularly.
• TCP/IP has been described as the “language of the Internet”. TCP/IP allows many different kinds of computers, from personal computers to mainframes, to exchange information.
• The two main protocols in the TCP/IP suite are TCP and IP.
• TCP permits communication between the various computers on the Internet, while IP specifies how data is routed from computer to computer.
• To illustrate how TCP/IP works, consider either sending an email message or requesting a Web page.
• The information is “formatted” according to its specific application protocol:
  • Simple Mail Transfer Protocol (SMTP) - used for email message
  • HyperText Transfer Protocol (HTTP) - used for Web page request
• Assuming that TCP/IP software is installed on your computer, the information to be sent is split into IP packets, called packets for short and transmitted over the Internet.
• The advantages of packets are:
  • Error recovery - if a packet gets corrupted; only that small packet needs to be resent, not the entire message.
  • Load distribution - if one area of the network is congested, packets can be rerouted to less busy areas.
  • Flexibility - if the network experiences a failure or disruption in one locale, packets can be rerouted.