Queueing theory is significantly applicable to the performance prediction and modeling of various congestion problems in different frameworks. The queue theoreticians relate stochastic properties of the arrival and service processes to predict the performance measures of the queueing systems. The terms queue length refers to the number of customers in the queueing system, including the customers in service. System performance estimation is often based on the advancement and analysis of appropriate models. The growth of queueing models can be traced broadly on two parallel tracks namely: (i)...