• _{Wide area network is a network which covers a larger geographical area than a LAN and where telecommunications links are implemented, normally leased from the appropriate PTO(s). Examples of WANs include packet switched networks, public data networks and Value Added Networks}
  • _{Packet switched networks use packet switching. Packet switching is a method of switching data in a network. Individual packets of a set size and format are accepted by the network and delivered to their destination. The sequence of packets is maintained, and destination established, by the exchange of control information (also contained in the packets) between the sending terminal and the network before the transmission starts. The network is open to all users, all the time, with packets from the various nodes being interleaved throughout the network. The packets can be sent in any order, as the control information sent at the beginning of the transmission ensures they are interpreted in the correct order at the receiving end. Because each packet carries its own control instructions, it can use any route to reach its destination. The link lasts only as long as the transmission.}
  • _{Public Data Network is a network established to provide data transmission services for public use.}
  • _{Van (Value Added Network)/Vans (Value Added Network Service) A data transmission network which guarantees data security and integrity through added computer control and communications, from the sender to the recipient often in the manner of a door-to-door courier or freight forwarder.}