A service provisioning system is examined, where a number of servers are used
to offer different types of services to paying customers. A customer is charged
for the execution of a stream of jobs; the number of jobs in the stream and the
rate of their submission is specified. On the other hand, the provider promises
a certain quality of service (QoS), measured by the average waiting time of the
jobs in the stream. A penalty is paid if the agreed QoS requirement is not met.
The objective is to maximize the total average revenue per unit time.