3Com CoreBuilder 9000, User Manual

Page: 307 / 468

10
ATM N
ETWORK
B
ASICS
This chapter provides basic concepts and information about:
ATM Overview
ATM Cell Structure
ATM Layers
Functional Planes
Designing ATM Networks
ATM Network Examples
LAN Emulation ATM Networks
ATM Overview
In 1986, the Comité Consulatif International Télégraphique et
Téléphonique (CCITT), now known as the International
Telecommunications Union (ITU), formed a study group to explore the
concept of a high-speed, integrated network to uniformly handle voice,
data, and a variety of other services. Their research resulted in
Asynchronous Transfer Mode (ATM), a telecommunications concept
defined by CCITT and ANSI standards for carriage of a complete range of
user traffic on any User-to-Network Interface (UNI) and to facilitate
multimedia networking between high-speed devices at multi-megabit
speeds.
Asynchronous Transfer Mode (ATM) is a high-speed networking
technology that utilizes packets of a fixed length. ATM uses logical
connections to provide quality of service guarantees that enable disparate
traffic such as data, voice, and video to be carried over the same local
area network (LAN) or wide area network (WAN).