Page 82 of 378 ITG Engineering Guidelines
553-3001-202 Standard 1.00 April 2000
4Refer to Poisson P.01 Table to find ITG ports required to provide a
blocking Grade of Service of 1% assuming Poisson random
distribution of call origination and zero correlation among calls.
Note:
A lower Grade of Service, such as P.10, may be preferred if
overflow routing is available through the PST N, circuit-switched VPN,
or ITG ISL TIE trunks.
For P.01 blocking Grade of Service the number of trunks (I TG ports) in
Table 12 on page 94 which provides a CCS higher than T is the
solution.
For P.10 blocking Grade of Service, refer to Table13 on page 95.
5Calculate bandwidth output. Refer to Table5 (silence suppression
enabled) or Table6 (silence suppression disabled). Tv/36 and Tx/36
indicate the average number of simultaneous caller s.
Note:
This calculation requires perfectly queued, and perfe ctly
smooth traffic.
Tv/36*bandwidth output per port = voice bandwidth per node (Bv)
Tx/36*bandwidth output per port = fax bandwidth per node (Bx)
Total bandwidth (Bt) = Bv + Bx
For WAN calculation, only the larger of fax traffic sent or rec eived
needs to be considered.
6Adjust requirement for traffic peaking
Peak hour bandwidth per node = Bt*1.3 (default)
A peakedness factor of 1.3 is the default value used to account for
traffic fluctuation in the busy hour due t o non-queued, Pois son random
distribution of call originations.
The procedure shown here is for ITG port and T-LAN data requirement calculation. In the WAN environment, traffic parcel i s defined p er desti nation pair (route). The total node traffic s hould be sub-divi de d into d esti nat ion pai r traffic. The rest of calculation procedure continues to be applicable.Example 1: ITG ports and T-LAN Engineering (silence suppression enabled)