Service differentiation of variable bit rate voice in AAL2 multiplexers

Abstract

Many of the voice codecs in use today employ silence-suppression techniques to suppress packet generation during silence periods, resulting in output voice traffic that is variable bit rate (VBR) in nature. ATM Adaptation Layer Type 2 (AAL2) is recommended for use as the basic switching and multiplexing technology for third generation mobile access networks since it allows for efficient and low delay transport for these VBR streams. We give quantifiable quality of service (QoS) description of the requirements for real time signal transfer and explore the possibility of service differentiation within the AAL2 multiplexer for different classes of voice calls. It has been found that a 9% increase in trunking; bandwidth efficiency can be obtained when employing service differentiation and priority queuing techniques-over the more common first in first out (FIFO) single queue system.