The interface between services, such as voice, and the internal ATM switching protocol.
The layer in the ATM protocols that represents layers four through seven in the OSI seven layer protocol stack. The protocol that turns packets into cells.
A set of processes defined to adapt information for transmission in discrete cells across a network. Multiple AALs are defined for various traffic types. Click here to view a diagram.
Where non-ATM data is converted to ATM format by filling the 48-byte fixed-length cells at the UNI. Forms the top layer of the ATM version of the BISDN protocol stack. AAL is divided into two sublayers: Convergence Sub-layer and Segmentation and Reassembly Sub-layer.
The highest layer of the ATM model, which roughly corresponds to thenetwork layer of the Open Systems Interconnection (OSI) model. The ATM adaptationlayer consists of four AAL protocols, each of which formats packets differentlyto support different types of transmissions, such as audio, video, and data.
A protocol layer that segments incoming data into ATM cells.
A set of standard protocols that translate user traffic into a size and format that can be contained in the payload of an ATM cell. User traffic is returned to its original form at the destination. This process is called segmentation and reassembly. All AAL functions occur at the ATM end-station rather than at the switch.
The ATM layer that is responsible for the adaptation of the information of the higher layer to the ATM cells. It is composed of two layers, the Segmentation and Reassembly sublayer and Convergence sublayer. ATM Adaptation Layer 1 supports CBR voice and video network services. ATM Adaptation Layer 2 supports VBR voice and video network services. ATM Adaptation Layer 3 supports VBR connection oriented data services. ATM Adaptation Layer 4 supports VBR connectionless oriented data services. ATM Adaptation Layer 5 supports connectionless variable bit rate data (e.g., IP or signaling) over ATM.
The layer of the ATM protocol stack that parses data into the payload portion of the ATM cell for transport across an ATM network. See also: Asynchronous Transfer Mode (ATM)
