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THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1956 



The proportion of load overflowing the group is then 0.0472/4.50 = 

 0.0105, which agrees, of course, with the Erlang £^i,io(4.5) value. The 

 successive overflow values are shown on the chart by the row of dots 

 along the a2 and V2 1-trunk curves. 



Instead of considering successive single-trunk overflows as in the ex- 

 ample above, other numbers of trunks may be chosen and their over- 

 flows determined. For example suppose the 10 trunks are subdivided 

 into 2 + 3 + 2-1-3 trunks. The loads overflowing these groups are 

 given in Table XIX. 



Again the overflow is 0.0472 erlang, or a proportion lost of 0.0105, 

 which is, as it should be, the same as found in the previous example. 

 The values read in this example are indicated by the row of dots marked 

 1, 3, 6, 8 on the 2-trunk and 3-trunk curves. 



The above procedure and curves should be of use in obtaining an esti- 

 mate of the character of the overflow traffic when a non-random load 

 is offered to a group of paths. 



I 





Table XIX — Sucessive Non-Random Overflows 



