some waiting line systems there is a specific, limited number of potential customers that can arrive at the service facility. This is referred to as a finite calling population .
a good example iskamwangi Manufacturing operates a shop that includes 20 machines. Due to the type of work performed in the shop, there is a lot of wear and tear on the machines, and they require frequent repair. When a machine breaks down, it is tagged for repair, with the date of the breakdown noted and a repair person is called. The company has one senior repair person and an assistant. They repair the machines in the same order in which they break down (a first-in, first-out queue discipline). Machines break down according to a Poisson distribution, and the service times are exponentially distributed.
The finite calling population for this example is the 20 machines in the shop, which we will designate as N .