On the orbit characteristics of the M/G/1 retrial queue

In teletraffic applications of retrial queues only the service zone is observable. Another part of a retrial queue, the orbit, which represents the delay before repeated attempts to get service, cannot be observed. Thus, it is very important to get general results about behavior of the orbit. The authors investigate two characteristics of the orbit, namely, the orbit busy period and the orbit idle period, which seems to be very useful from this point of view.