Moreover, in many cases tail is the case of switching from one queue to another switching- jockeying. Many guests also come in groups, as in example of the village cinema, where they come in groups, or individually. Very different is the way of how to address arrivals when the customer population can be considered infinite. In any case, the above behavior is very difficult to predicted and studied. When the system client is a man and not an object enter the customer psychology queue system factors and therefore not measurable in mathematical terms. For example, withdrawal phenomena may occur more frequently in a stochastic waiting time wherein customer knows how long it will last or a wait that is not strict discipline the queue, but customers following, first served.

A process that will require successive service and queues can hold customer more if it is in the middle of the process, but generally process of service, even if it lasts more than waiting, make customers more patient. Many factors such as the aforementioned hinder the designer of a queuing system and make strict mathematical study impractical.. Discipline tail the element of discipline in the description of a queuing system it refers to the method by which selects the next customer from a crowd customers waiting in line. Thus, the most simple and fair method is method first in first out fifo, or else first come first served fcfs, during which the customer has entered first in the queue, by all customers waiting, they are first to emerge from it. Examples of such tails found in each department, fund, etc. The reverse process is the last in first out lifo, whereby the last to join the queue is the first to come out.

An example of such is a queue stack dishes orcars customer queue system software free on a ship. The last of the dishes loaded in the stack they are the first to get it. Another method is the selection of next customer in luck. Finally, customers can be chosen priority, as, for example, the selection of passenger baggage business class priority than its economy class passengers. In this case there are two different versions. First embodiment, the simple priority or priority without interruption non preemptive, in which, after over the customer selected the customer with the highest priority of those in the queue. Further characteristic size of the queue is the size that can be considered infinite or finite in this capacity. When the capacity is reached, the system will not be able to accommodate additional customers blocked.

A queue system software second embodiment, absolute priority or priority interruption preemptive, in which, when a customer enters the queue, if someone served customer with a lower priority is stopped and started his own service. In summary, then, the choice of customers from the queue it is primarily one of the following waysfirst-come-first-served fcfs or first-in-first-out fifo last-come-first-served lcfs or last-in-first-out lifo priority without interruption non preemptive priority to interruption preemptive service in random order siro or just random there are still, queues, in which like next to serve client who requires the smallest or the largest time service, or that with the lowest queue system software completion deadline, which makes study the most complex process.