Currently learning about Networks in Computer Science, and I don't understand why you would ever use an ATM (asynchronous transfer mode) network instead of IP, as IP doesn't have to be as reliable and can be set up much more quickly, and is what the entire Internet basically uses.
ATM gives you a defined, guaranteed bandwidth once a connection is setup. Therefore it is great when you wish to replace “end to end” leased lines, with a network that can be configured without having to physically change cable connections. (ATM is still used a lot inside of BT (UK) telephone exchanges to allow line cards to be connected to different “providers” without having to reconnect the phone wires.)
For example you need to read data values from a remote sensor at 32 kbs, and you can’t cope with a single value being lost or delayed. Another example is CCTV when you want wish to have any dropped frames.
However it is cheaper these days to have a IP network that is ten times faster than you need, compared to a ATM network at the speed you need…… IP got the mass market and the computer network vendors sold their kit for a lot less then the telecom equipment vendors.
This was partly due to the telecom service providers demanding lots of “bells and whistles”, then deciding once the telecom equipment vendors had designed what was asked for, that “of the shelf” Ethernet switches where good enough. So the customer was wrong, resulting in most large telecom equipment vendors closing down.
Therefore an ATM connection is superior to a IP connect when you need a continues fixed bandwidth and someone will sell you a ATM connect for a not much greater price then a IP connection!
AFAIR ATM was specifically designed to also transfer real time data like voice. This requires guaranteed properties like bandwidth and latency.
IP can't give those guarantees as it looses packets and reorders packets.
Also ATM is connection oriented, whereas IP needs the complexity of TCP to get that.