N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 4 - ATM Technology                                                                                                                      Slide 27 of 46 _________________                                                                                  __________

                              ATM Hardware and Software Requirements

                                Adaptation Devices

                                ATM Switches

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ATM networks have two types of equipment: Adaptation devices and ATM switches. Both are designed using specifications developed by ATM standards.

Adaptation Devices - These devices perform the functions of the ATM Adaptation Layer to convert voice, data and video information for ATM cells. The Adaptation Devices interface with the ATM switch. A Hub, a Concentrator and a Network Interface Card provide ATM Adaptation Layer functions. A Hub provides bandwidth to LAN subscribers by aggregating on higher speed access lines to the backbone. A Concentrator adapts information from low speed devices or special applications for transmission over an ATM network. A Network Interface Card used in a server or a workstation adapts the information for direct access to an ATM switch.

ATM Switches - ATM switches provide a variety of interfaces, application conformance, availability and manageability. There are ATM switches, known as Virtual Path switches, which provide switching of multiple virtual channels simultaneously. Virtual channel switches are used to switch individual channels of user information. Virtual channel switches are deployed in the Access layer and Edge Layer of the network. These switches are also deployed in corporate sites and university campus sites. Backbone switches are used with high bandwidth transmission facilities.