ASYNCHRONOUS TRANSFER MODE SYSTEM HANDLING DIFFERING AAL PROTOCOLS

摘要

A communications network (40) has ATM cells with AAL2 protocol packets carried on a first interface (54) between two nodes (42, 44) of the network. Using the AAL2 protocol packets, many user channels are multiplexed onto one ATM VC between the two nodes. In one of the two nodes designated as a control node (44), user channels are terminated by mapping AAL2 packets of the user channels into modified ATM cells having an AAL protocol different than AAL2. The AAL protocol utilized for the modified ATM cells, termed AAL2 prime, requires that AAL2 packets carried in the ATM cell payload be whole packets and that the ATM payload not have an AAL2-type start field. Preferably, in the AAL2 prime protocol only one whole AAL2 packet is carried per ATM cell payload. Termination of the AAL2 user channels at the control node preferably occurs at a pooled and centralized resource termed a cell handling unit (32). The provision of the cell handling unit (32) and the AAL2 prime protocol advantageously allows standard ATM equipment, e.g., an ATM switch (30), to be employed. A mobile telecommunications network is provided as an example illustrated embodiment.