Performance evaluation of multiplexing AAL2 voice traffic and TCP/IP data at the ATM cell level

ATM adaptation layer type 2 (AAL2) has been standardized to carry highly compressed voice traffic with silence suppression over an ATM network. The ITU-T recommends using the constant bit rate (CBR) for ATM service carried through an AAL2 virtual channel (VC) to guarantee voice quality. However, the traffic characteristic of AAL2 VC is variable bit rate (VBR), which is different from that of the TCP/IP data traffic at the ATM cell level by two multiplexing techniques: priority multiplexing and non-priority multiplexing. Priority multiplexing enables the transfer to TCP/IP data with the AAL2 voice quality guaranteed. Non-priority multiplexing can enable the application of VBR services through AAL2 under certain conditions, and can thus help optimize transmission efficiency in the ATM backbone network.