Nortel Networks NN43001-563 - page 98

98 ITG engineering guidelines
Procedure 5
Calculating IP Trunk3.01 (and later) por t and bandwidth requirements
Step Action
1Calculate VoIP trafficdur ing busy hour.
CCS/user = 4*150/100 = 6 CCS
Tv = 120*6 = 720 CCS
2Calculate fax on IP traffic during busy hour.
CCS/fax sent = 3*48/100 = 1.44 CCS
CCS/fax received = 5*48/100 = 2.4 CCS
Totalfax CCS (Tx + Rx) = 1.44*25 + 2.4*20 = 36+ 48= 84 CCS
3Calculate IP Trunk3.01 (and later) traffic during busy hour.
Totaltraffic (T) = Tv + Tx = 720 + 84 = 804 CCS
4Refer to the Poisson P.01 table (Table10 "Trunk traffic, Poisson 1
per cent blocking Grade of Service" (page 99)) to find the number
of IP Trunk3.01 (and later) por ts required for 1% blockingGrade of
Service. For P.10blocking Grade of Service, refer to Table 11 "Trunk
traffic Poisson10 per cent blocking Grade of Service" (page 100).
804 CCS can be served by 35 IP Trunk3.01 (and later) ports
with P.01blocking Grade of Service. TwoITG-Pentium 24-port
trunk cards are needed to serve this customer.
5Calculate average bandwidth use on the TLAN subnet.
For voice:
720/36*30.7 = 614 kbit/s
For fax:
84/36*46.1 =108 kbit/s
Totalbandwidth = 614 + 108 = 722 kbit/s
6Adjust requirement for traffic peaking
Peak hour bandwidth requirement = 722*1.3 = 939 kbit/s
This is the spare bandwidth a TLAN subnet requires to transmit
the VoIP and fax traffic. Nortel recommends that the TLAN
subnet handle IP Trunk3.01 (and later) traffic exclusively.
—End—
Nortel Communication Server 1000
IP TrunkFundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
Copyright© 2007, Nor tel Networks
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