Packing density of voice trunking using AAL2

AAL2 has been adopted in ITU-T and ATM Forum to reduce the packing delay for voice trunking. A parameter called "timer CU" is used in AAL2 to avoid prolonged delay for any packet. However, the AAL2 documents do not discuss how to set the timer CU value. We establish a Markov chain model to analyze the AAL2 packing process. We find that the packing density and link efficiency depend significantly on the timer CU value. The analysis of this paper gives an algorithm to calculate a reference timer CU value to achieve desired link efficiency. Simulation results that verify the analysis are also presented.