468 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1956 



Fig. 27 — Comparison of losses on three graded arrangements of 22 trunks. 



that order. The results of extensive simulations made by Neovius on the 

 three trunk plans are available for comparison.* The values so obtained 

 are seen to be very close to the ER theoretical ones ; moreover the same 

 order of preference among the three plans is indicated and with closely 

 similar loss differentials between them. 



7.3.1. Throwdown Comparisons with Equivalent Random Theonj on 

 Simple Alternate Routing Arrangements with Lost Calls Cleared 



Results of manuallj' run throwdowns on a considerable number of 

 non-symmetrical single-stage alternate route arrangements are available. 

 Some of these were shown in Fig. 20; they represent part of a projected 

 multi-alternate route layout (to be described later) for outgoing calls 

 from the local No. 1 crossbar Murray Hill-6 office in New York to all 

 other offices in the metropolitan area. The paths hunted over initially are 

 called direct trunks; they overflow calls to Office Selector Tandem (GST) 

 groups, numbered from 1 to 17, which are located in widely dispersed 

 central office buildings in the Greater New York area. 



* Loc. cit. 



