96 ITG engineering guidelines
CCS/user=# of calls/ * Average Holding Time (in seconds)/100
Totalvoice CCS (Tv) = CCS/user x No. of VoIPusers
The number of VoIPusers (telephones) is the potential population
in the system that can generate/receive traffic through the IP Trunk
3.01 (and later) node. This number may be estimated for a new
Meridian 1 customer.
If the installation is for an existing customer, base the VoIPtraffic on
measured route traffic from traffic report TFC002, which provides
CCS for each route. A customer must determine the amount of
expected private network voice traffic.
2Calculate Fax on IP traffic
CCS/user sending fax = # of pages sent/fax* Average Time to send
a page (default 48 seconds)/100
CCS/user receiving fax = # of pages received/fax* Average Time
to receive a page (default 48 seconds)/100
Totalfax CCS (Tx) = CCS/fax sent*No. of users sending fax +
CCS/fax received* No. of users receiving fax
The user sending or receiving a fax can be the same person or
different persons. It is the number of faxed documents and the
average number of pages per faxeddocument that are impor tant.
The time unit for fax traffic is also the busy hour. The busy hour
selected must be the hour that gives the highest combined voice
and fax traffic.
3Totalthe ITG CCS.
TotalIP Trunk 3.01 (and later) traffic (T) = Tv + Tx
4Refer to PoissonP.01 table to find IP Trunk3.01 (and later) por ts
required to provide a blocking Grade of Service of 1% assuming
Poisson random distribution of call origination and zero correlation
among calls.
A lower Grade of Service, such as P.10,may be preferred if overflow
routing is available through the PSTN, circuit-switched VPN, or ITG
ISL TIE trunks.
For P.01blocking Grade of Service, the number of trunks (IP Trunk
3.01 (and later) ports) in Table10 "Trunktraffic, Poisson 1 per cent
blocking Grade of Service" (page 99) which providesa CCS higher
than T is the solution. For P.10 blocking Grade of Service, refer
to Table11 "Trunk traffic Poisson 10 per cent blocking Grade of
Service" (page 100).
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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