N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 4 - ATM Technology                                                                                                                      Slide 6 of 46 _________________                                                                                  __________

                                                What is ATM Technology ?

                                            A Method of Transporting Information

                                            High-Speed Cell Transmission

                                            802.6 Cell

                                            Cell Routing

_________________                                                                                  __________

ATM was developed to solve communications problems: such as transmission of voice, data and video information, and transporting multi-media user traffic over SONET networks. ATM is a core network protocol, an enhancement to the 802.6 MAN protocol, geared towards multi-media applications requiring bulk data transfer. With ATM, the intelligent networking devices can take advantage of the telephone companys' much improved network facilities. Frame Relay makes use of ATM in it's core network.

A Method of Transporting Information - ATM is a switching standard for multimedia services. ATM switches switch cells rather than bits or bytes.

High-Speed Cell Transmission - The fixed cells are switched by hardware-based mechanisms within ATM switches, enabling cell switching at a very high speed.

802.6 Cell - All ATM cells are fixed in size containing 53 bytes. Voice, data and video information is chunked into 53 byte cells for transmission over a single facility. ATM fills the cell position on a first come basis.

Cell Routing - The ATM switch interprets the cell header and routes the cell through the switching fabric to its destination.