There are many future benefits to ATM networking. One main beneficial factor of ATM networking will be the money saved by the end user. Others examples may include doctors accessing digital medical images at one time, video conferencing, or video on demand. The idea behind ATM was instead of always identifying a connection by the bucket number, just carry the connection identifier along with the data in any bucket, and keep the size of the bucket small. By keeping the bucket small, if any one bucket got dropped enroute due to congestion, not too much data would get lost, and, in some cases, could easily be recovered. In ATM, there are two points that are connected together by an identifier called the Virtual Circuit Identifier (combined with a Virtual Path Identifier) or VCI (and VPI) for short. The header of the packet transports the VCI and is carried in a bucket also. The only difference is it does not have a label or a designation for the bucket. These VCI labels are controlled by network nodes and are random while connections are established and eliminated. The address part of the VCI label will never be more than 24 bits! 

ATM uses cell relay, a fast-packet switching technology. Traditionally, most networks are either circuit-oriented, for delivering delay-sensitive information such as video or voice, or packet-oriented, for high-speed data transmission. Circuit switching guarantees end-to-end delivery and response times, but it can waste expensive bandwidth. Packet switching optimizes the use of bandwidth, but has variable packet delivery times. Packet switching can be unsuitable for isochronous traffic because of the amount of delay between packets, resulting in jittery transmission. "ATM combines the reliability of circuit switching with the efficiency of packet switching, giving you the best way to deliver all types of data. Through simplified packet-switching techniques, ATM segments packets into 53-byte cells." The ATM cell or packet is as specified by the T1S1 sub-committee and contains a 5 byte header as well as a 48 byte payload (information field). The reason for choosing a fixed-size packet is to ensure that the switching and multiplexing function could be carried out quickly and easily. Besides having the fixed packet, it is also small. This is a good idea since there will be a smaller propagation delay at the switch and in turn increasing the speed or throughput of the system. The cell’s small size also makes them more efficient in mixed-media networks because time sensitive
video and voice transmissions are not delayed by longer cells containing data traffic. The only problem with the cell size is that it is inefficient for data-only transmissions because approximately 20% of ATM’s bandwidth is taken up by header and administrative routing data. Users can get higher efficiencies on a LAN using a longer frame. For more information about ATMs go to the following links: 

LINKS TO OTHER PAGES CONTAINING ATM INFORMATION: 

   1. ATMs 
    2. ATM Detailed Information 
    3. Wireless ATM