In this paper a finite-source retrial queuing system with collision of the customers
is investigated by means of computer simulation. The server is not reliable; it is
subjected to breakdowns, and the repairs depend on whether the state of the server
is idle. The random variables used in the model are jointly independent and are exponential
and gamma distributed. Two operation modes are considered in the case of busy breakdown.
The novelty of the investigation is a comparison of the performance measures of these
modes, and estimations obtained by the simulation are graphically illustrated showing
the influence of the difference of the working modes on the performance measures such
as mean and variance of the response time, mean and variance of the number of customers
in the system, mean and variance of the sojourn time in the orbit, mean and variance
of time time a customer spent in service.
