On the definition of ATM traffic descriptors for LAN sources

Applying a multistage analytical model that is able to describe typical LAN services, this paper focuses on the characterization of LAN egress traffic in terms of the well defined traffic descriptors established in the international standardization fora. To exploit the statistical multiplexing gain offered by ATM, the paper investigates the performance of various LAN traffic control mechanisms. The paper shows that spacing to a predefined peak cell rate (PCR) may result in traffic streams with unpredictable burst size and connection scale required bandwidth. In this respect the statistical multiplexing gain is not exploitable but also the generic cell rate algorithm (GCRA) used in the usage parameter control (UPC) device for policing traffic, is not able to meet quality of service (QoS) demands. To overcome this situation, and to guarantee a predictable LAN egress traffic enabling statistical multiplexing and policing, a GCRA-based shaping mechanism is developed and evaluated.