BANDWIDTH ALLOCATION FOR ISOCHRONOUS CONNECTIONS IN DQDB USING THE PASCHEME

The PA scheme in DQDB is suitable for constant-rate and connection-ori ented transmissions. In this paper, we propose and evaluate four bandw idth allocation policies, which are based on the harmonic case of the pinwheel scheduling algorithm(1,2) for isochronous connections using t he PA scheme. The idea is to classify isochronous connections into sev eral harmonic classes according to their periods. Isochronous connecti ons from the same class can share the same unit channel as long as the total bandwidth is no greater than the available bandwidth they reque sted in the unit channel. The main advantage of our schemes is that al l isochronous connections can be established with zero variability. Th e proposed policies are evaluated in terms of their blocking probabili ties and processing overhead via both simulation and analysis.