378 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



1.0 



8 



0.01 

 8 



a. 001 



8 

 6 



0.0001 



01 23456789 10 



t/h = DELAY IN MULTIPLES OF AVERAGE HOLDING TIME 



Fig. 16 — Delayed traffic served in random order, exponential holding times, 

 c = 20. 



portion of calls delayed is found to be P( > 0) = 0.41 (Fig. 14) . The proba- 

 bilities of exceeding delays of t/h = 0.6 and 1.8 holding times are cal- 

 culated for calls served in order of arrival by equation (1), in the following 

 table: 



Comparing the queued and random handling of delayed calls one finds 

 the perhaps unexpected result that with random handling some 2 per 

 cent /either calls are delayed longer than 1 minute than if perfect queueing 

 had been present. This is due to the characteristic shapes of the two types 



