Abstract
This paper considers a queuing model with batch Poisson input and two heterogeneous servers, where the service times are exponentially distributed. The faster server is always on, but the slower server is only used when the queue length exceeds a certain level. Traditionally, this was done through scheduling policy. In this paper an enhanced algorithm, called fuzzy scheduling policy, is suggested using fuzzy reasoning to achieve the benefits of heterogeneity in service rates. Uncertainty associated with queue congestion estimation and lack of mathematical model for estimating heterogeneity in service rates makes the fuzzy scheduling algorithm the best choice. Extensive performance analysis via simulation showed the effectiveness of the proposed method for congestion detection and avoidance improving overall queuing systems.