ATM 101 Asynchronous Transfer Mode

Written by: Karsten Kramer - Jul 24, 2008

No, this isn't your corner ATM machine. In telecommunications and data communications circles, A.T.M. stands for Asynchronous Transfer Mode, and is a type of data service.

While many carriers are now running their voice, data, and Internet services over IP enabled networks, one of the first steps to a more efficient carrier network involved running an ATM core newtork.

We'll write more about how carriers utilize ATM in another article, but for now, let's focus on how individual businesses and large enterprise customers can use ATM.

A long time ago, if you wanted to connect two or more computer networks together from different ends of town, or across the country, you would have to get a private line, or leased line, from a carrier to connect the two locations. As the number of of locations increased, or the distance between the locations grew, the more expensive each connection became for the carrier, and of course, for the customer.

To streamline connections and costs, carriers began to install Frame Relay switches in local markets, and connected them via a Frame Relay network, allowing for local customers to buy a connection into the nearest Frame Relay switch, and let the network route the traffic between the customer's locations in a more efficient manner, as traffic warranted, instead of paying for dedicated connections end to end, tying up more real estate in the carrier's network.

Similarly, ATM was another evolution of this concept. ATM had many benefits over frame relay, mainly bigger connection capacity, and more Quality of Service (QoS) possibilities.

With ATM, customers could connect more locations together, or to a headquarters location, and could run more bandwidth intensive applications, such as Voice over IP (VoIP), video conferencing, streaming video, etc.