“…The variations and extensions of these vacation models were developed by several researchers such as Lee et al [3,4], Krishna Reddy et al [5], Choudhury [6,7], Ke [8,9], Ke and Chu [10], Ke et al [11,12] and many others. A numbers of papers [13][14][15][16] have recently appeared in queueing literature in which the server provides to each heterogeneous service with Bernoulli schedule vacation (BSV). The so-called BSV means that when the service of a unit is completed, the server may leave for a vacation of random length with probability p or may continue to serve the next unit, if any with probability 1 脌 p (see Choudhury et al [17]).…”