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BELL SYSTEM TECHNICAL JOURNAL 



the total load as pictured in Fig. 5. A trunk is represented by each 

 horizontal line, and the load submitted by the vertical arrow, as 

 though it were starting at the bottom of the group to hunt for the first 

 idle trunk. We first observe that the proportion of calls lost on the 



30 40 50 60 70 

 C = NUMBER OF TRUNKS 



Fig. 3 — Load carried by a trunk group at a constant loss. 



average in the split groups cannot be less than in the complete group 

 since when all the trunks are full in either case the calls coming in will 

 be delayed or lost altogether, and only when all 20 trunks are occupied 

 in the case of the complete group will calls be lost. On the other hand, 



^ 0.5 



10 20 30 40 50 60 70 80 90 100 



C - NUMBER OF TRUNKS 



Fig. 4 — Load carried per trunk at a constant loss. 



