Asynchronous Transfer Mode(ATM) is a "high-speed transmission protocol in which data blocks are broken into small cells that are transmitted individually and possibly via different routes in a manner similar to packet-switching technology". In other words, it is a form of data transmission that allows voice, video and data to be sent along the same network. In the past, voice, video and data were transferred using separate networks: voice traffic over the phone, video over cable networks and data over an internetwork. ATM is a cell- switching and multiplexing technology designed to be a fast, general purpose transfer mode for multiple services. It is asynchronous because cells are not transferred periodically. Cells are given time slots on demand. What seperates ATMs is its capability to support multimedia and integrate these services along with data over a signal type of transmission method. The ATM cell is the data unit used to transmit the data. The data is broken into 48-byte data packets for transmission. Five bytes of control data are appended to the 48-byte data packets, forming a 53-byte transmission frame. These frames are then transmitted to the recipient, where the 5-byte control data (or Header) is removed and the message is put back together for use by the system In an ATM network, all data is switched and multiplexed in these cells. Each ATM cell sent into the network contains addressing information that achieves a virtual connection from origination to destination. All cells are then transferred, in sequence, over this virtual connection. Asynchronous ...
