Asynchronous Transfer ModeAsynchronous Transfer Mode (ATM) is a "high-speed transmission protocol in which blocks of data are divided into small cells that are transmitted individually and possibly across paths different in a similar way to the package-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 on the telephone, video on cable networks, and data on one network. 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 assigned time slots upon request. What sets ATMs apart is their ability to support multimedia content and integrate these services alongside data via a signal-type transmission method. The ATM cell is the data unit used to transmit data. The data is broken into 48-byte data packets for transmission. Five bytes of control data are added 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 (oHeader) is removed and the message is reinserted. 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 makes a virtual connection from source to destination. All cells are then transferred, sequentially, over this virtual connection. Asynchronous Transfer Mode: The header includes information about the payload content and transmission method. The header contains only 5 octets. It has been shortened as much as possible, containing the minimum address and control functions for a working system. The sections in the header are a series of bits that are recognized and processed by the ATM layer. The sections included in the header are Generic Flow Control (GFC), Cell Loss Priority (CLP), Payload Type, Header Error Control, Virtual Path Identifier, and Virtual Channel Identifier. The header is the information field that contains the payload that supports the revenue. A GFC is a 4-bit field intended to support simple multiplexing implementations. The GFC is intended to support flow control. The CLP bit is a 1-bit field that indicates the loss priority of a single cell. Cells are assigned a binary code to indicate high or low priority.