Nortel Networks NN43001-563 User Manual

Page 97

IP Trunk 3.01 (and later) traffic engineering

This calculation requires perfectly queued and perfectly smooth
traffic.

Tv/36*bandwidth output per port = voice bandwidth per node (Bv)
Tx/36*bandwidth output per port = fax bandwidth per node (Bx)
Total bandwidth (Bt) = Bv + Bx

For WAN calculation, consider only the larger of fax traffic sent or
received.

Adjust requirement for traffic peaking.

Peak hour bandwidth per node = Bt*1.3 (default)

—End—

Procedure 5 "Calculating IP Trunk 3.01 (and later) port and bandwidth
requirements" (page 97)

is used to calculate IP Trunk 3.01 (and later)

port and, therefore, IP network bandwidth requirements. In the WAN
environment, the traffic parcel is defined for each destination pair (route).
The total node traffic should be sub-divided into destination pair traffic. The
rest of the calculation procedure continues to apply.

Example 1:
IP Trunk 3.01 (and later) ports and bandwidth engineering (Silence
Suppression enabled)

In this configuration example of 120 VoIP users, each user generates four
calls using the IP network (originating and terminating) with an average
holding time of 150 seconds in the busy hour.

In the same hour, 25 faxes were sent and 20 faxes received. The faxes sent
averaged 3 pages, while the faxes received averaged 5 pages. The average
time to set up and complete a fax page delivery is 48 seconds.

The codec of choice is G.729AB, voice packet payload is 30 ms. The fax
modem speed is 14.4 kbit/s and payload is 16.6 ms. How many IP Trunk
3.01 (and later) ports are needed to meet P.01 blocking Grade of Service?
What is the traffic in kbit/s generated by this node to the TLAN subnet?

Follow the steps in

Procedure 5 "Calculating IP Trunk 3.01 (and later) port

and bandwidth requirements" (page 97)

to calculate IP Trunk 3.01 (and

later) port and bandwidth requirements.

Procedure 5

Calculating IP Trunk 3.01 (and later) port and bandwidth requirements

Step

Action

Calculate VoIP traffic during busy hour.

Nortel Communication Server 1000

IP Trunk Fundamentals

NN43001-563

01.01

Standard

Release 5.0

30 May 2007