ANALYSIS AND ENGINEERING OF A VOICE DATA PACKET MULTIPLEXER/

This paper investigates performance and engineering issues concerning a multiplexer scheme that has been implemented in AT&T's Integrated Ac cess Terminal (IAT) to transport packetized voice and data traffic on shared facilities. The multiplexer serves voice and data traffic accor ding to a dynamic bandwidth allocation scheme in order to simultaneous ly meet their performance requirements. A bit-dropping procedure is em ployed for voice packets to provide a graceful degradation of voice qu ality under overload conditions. An analytical model is developed for the multiplexer service scheme that estimates performance parameters g iven the voice and data offered loads. The model is used to demonstrat e the capacity advantages of dynamic bandwidth allocation, and to gene rate load-service curves that illustrate the tradeoffs of carrying dif ferent combinations of voice and data traffic on the multiplexer. Sens itivity of voice and data performance to the multiplexer time-slice pa rameters is also investigated. The model is readily embedded in a desi gn approach that determines the bandwidth required to carry the voice and data traffic demands while satisfying all desired performance obje ctives.