Computer network technologies and services/Print version
Wan : Strictly speaking, a Wide Area Network (WAN) is a network that is extended over a broad area, spanning regions, countries or in the case of the Internet even the world. More generally, any computer networking technology used to transmit data over long distances can be called as a WAN.
A WAN technology should meet some requirements in terms of service duration, bit rate and delay constraints according to the application (telemetry, telephony, data transfer, etc.) it is designed for.
Asynchronous Transfer Mode (ATM) represents the convergence for a wide variety of technologies that in the past both telecom and IT worlds in parallel introduced in order to transmit data over long distances:
in the telecom world, the telephony turned from analog to digital, then ISDN and B-ISDN started to carry data along with the voice;in the IT world, Frame Relay superseded analog and digital leased lines by taking advantage of packet switching, and X.25 by moving the complexity from core to edge nodes.
Nowadays ATM is going to be abandoned in favour of IP thanks to its lower complexity and greater simplicity.