A Survey on Queueing Systems with Mathematical Models and Applications

Read this paper on waiting line analysis and queues. It provides a good survey of the theory and uses of this type of analysis. Pay particular attention to sections 1 through 3. How might these models be used to balance firm costs with different levels of customer satisfaction?

3. Components of Queueing System

3.4. The Service Discipline

Customers can be served one by one or in batches. There are many possibilities for the order in which they enter to the service venue. Some of the service facilities are as follows:

First Come First Served (FCFS): In this process, service is provided in the order of arrival. First comer gets the service first. Generally, this method is applied in the supermarket, billing counters, and many other queuing systems. It is called First In First Out (FIFO) as well.

Service In Random Order (SIRO): This is the method in which service is provided without any fixed rule. People can be observed randomly in security checkpoints. Service provider collects data randomly for statistical studies.

Last Come First Served (LCFS): It is the another method of providing service to the customers in which the last arrival gets service at first. This method is applied in the production line where the products are kept one over the other. While selling these products, the item kept at the top is sold at first though it is placed there at last.

Priorities: There can be some customers who need the service immediately for many reasons. Those customers could be in a rush or may take shorter processing time. Some emergency cases could also be there in the doctor's clinic and some would be ready to pay more for the quicker service.

Processor Sharing: Concept of processor sharing is specially applied in the communication system where computers divide their processing power equally over all the other computers. Number of customers can get access to the internet from a single router.

Round Robin (RR): This method can be seen mainly in cyclic queueing system in which either server or the customers move in a cycle. We have experienced a revolving dining table where customers are stationary but the server moves carrying different menu on the table.