Nortel 1000 Fundamentals page 15

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Number of Typical
UM Users BH Call
Duration
(seconds)
50 15000
100 30000
200 60000
500 150000
1000 300000
2000 600000
3000 900000
Communication Server 1000 with Microsoft Exchange Server 2007 Unified Messaging Fundamentals
Copyright © 2008 Nortel Networks
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Menu selection and call transfer time is 30 seconds, with a
completed call duration of 180 seconds.
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Busy Hour (BH) Auto Attendant usage is 0.35 calls per hour for
each Microsoft Unified Messaging user.
Auto Attendant operation requires the usage of two SIP trunks, which
remain in use for the duration of the call.
If Microsoft Unified Messaging system usage differs from the call model
described for the purpose of SIP trunk table calculations, it is the
responsibility of the customer to monitor the actual usage of the system
and ensure that there are sufficient SIP trunks available for use.
Typical BH Erlangs
CCS (ccs/36)
150 4.17
300 8.33
600 16.67
1500 42
3000 83
6000 167
9000 250
Nortel Communication Server 1000
NN43001-122 02.04
24 October 2008
Number of Number of
SIP Trunks SIP Trunks
(Erlang B (Erlang B
P05 Grade P01 Grade
of Service) of Service)
8 10
13 16
22 26
48 55
88 99
170 187
250 273
Overview 15
Number of
SIP Trunks
(Erlang B,
Non-blocki
ng)
24
33
49
89
147
254
355