Theoretical and practical aspects of telephone traffic

A detailed discussion of problems and possible means of measuring telephone traffic. It is stated that the flow of theoretical telephone traffic is fully defined by the distribution function of two independent random variables (the calls' holding time and their arrival time), and the problems concerning these two variables, both in subscriber and artificial traffic measurements, is dealt with. Busy-hour traffic and the associated grade of service form the basis of the theoretical considerations and this seems correct. Four methods are described for deriving the offered traffic from the the traffic carried by a group.