Nortel Networks NN43001-122 - Manual (Page 15)

Overview 15
— Menu selection and call transfer time is 30 seconds, with a
completed call duration of 180 seconds.
— 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.
Number of
UM Users Typical
BH Call
Duration
(seconds) Typical BH
CCS Erlangs
(ccs/36) Number of
SIP Trunks
(Erlang B
P05 Grade
of Service) Number of
SIP Trunks
(Erlang B
P01 Grade
of Service) Number of
SIP Trunks
(Erlang B,
Non-blocki
ng)
50 15000 150 4.17 8 10 24
100 30000 300 8.33 13 16 33
200 60000 600 16.67 22 26 49
500 150000 1500 42 48 55 89
1000 300000 3000 83 88 99 147
2000 600000 6000 167 170 187 254
3000 900000 9000 250 250 273 355
Nortel Communication Server 1000
Communication Server 1000 with Microsoft Exchange Server 2007 Unified Messaging Fundamentals
NN43001-122 02.04
24 October 2008
Copyright © 2008 Nortel Networks
.