Nortel Networks NN43001-563 User Manual

Page 96

ITG engineering guidelines

The number of VoIP users (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 VoIP traffic 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.

Calculate 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

Total fax 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 faxed document that are important.
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.

Total the ITG CCS.

Total IP Trunk 3.01 (and later) traffic (T) = Tv + Tx

Refer to Poisson P.01 table to find IP Trunk 3.01 (and later) ports
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.01 blocking Grade of Service, the number of trunks (IP Trunk
3.01 (and later) ports) in

Table 10 "Trunk traffic – Poisson 1% blocking

Grade of Service" (page 99)

which provides a CCS higher than T is

the solution. For P.10 blocking Grade of Service, refer to

Table 11

"Trunk traffic – Poisson 10% blocking Grade of Service" (page 100)

Calculate bandwidth output. Refer to

Table 17 "Silence Suppression

disabled TLAN Ethernet and WAN IP bandwidth usage per IP Trunk
3.01 (and later) " (page 113)

(Silence Suppression disabled). Tv/36

and Tx/36 indicate the average number of simultaneous callers.