The ATM adaptive layer (AAL) provides the interface from the user to the ATM system.
The AAL makes the ATM layer services more adaptable to specific services. The specific services may include user services, control services and management services. The AAL is the layer above the ATM layer and it is responsible for converting the information from the higher layers.
The two main functions of this AAL are:
- to provide functions needed to support applications
- to break up information into units that will fit into cells





