3-10 Provisioning guidelines
Default method
Studies have been conducted which estimate the average line
CCS/r
to
never be greater than 5.5 in 90 percent of all businesses. If attempts to
calculate the
CCS/r
using the comparative method or the manual
calculation have not been successful, the default-of 5.5 line
CCS/r
can be
used.
The network line usage is determined by multiplying the number of lines by
5.5
CCS/r.
The total is then multiplied by 2 to incorporate the trunk
CCS/r.
Unfortunately, when this method is used, the intra
CCS/r
is added
twice to the equation, and the result could be over provisioning if the intra
CCS/T is high.
Another difficulty experienced with this method is the inability to forecast
individual trunk groups. The trunk and intra CCS/T is forecasted as a sum
group total. Examples of the Default method and the Manual calculation
method are shown in Table 3-4 for comparison.
Default method example:
-
275
Stations at Cutover
-
304
Stations at 2 years
-
352
Stations at 5 years
Cutover 275 x 5.5 (CCWI’) x 2=3025 CCS Total System Load
2 Year 304 x 5.5
(CCS/r)
x 2 = 3344 CCS
Total System Load
5 Year 352 x 5.5 (CCS/T) x 2 = 3872
CCS Total System Load
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System engineering 553-3001-151