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. In this paper, 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.
Note: This study has been used in 3rd Generation Parternetship Project, Technical Report on "Delay Budget Within the Access Stratum," TR 25.853 V3.1.0, 1999.
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