ITG Engineering Guidelines Page 143 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
Estimate QoS level

You can use Table 24 to estimate the IP telephony QoS level based on QoS

measurements of the in t r an et . To limit the size of this ta b le , the packet loss

and one-way delay values are tabulated in increments of 1% and 10ms

respectively. The techniques used to determine and apply the information in

this table are Nortel Networks proprietary.

Table 24
ITG QoS levels (Part1 of 4)
Packet
loss (%)
One-way
delay (ms)
QoS level
G.729A G.711A/G.711u G.723.1
0 50-200 excellent excellent excellent
0 210-220 excellent excellent good
0 230-330 good excellent good
0 340-360 good good good
0 370-380 good good fair
0 390-620 fair good fair
0 630 -780 fair fair fair
0 790 fair fair poor
1 50-180 excellent excellent good
1 190-200 good excellent good
1 210-320 good good good
1 330-340 good good fair
Note:
The QoS levels are equi valent to the following MOS values: (See page 56 for m ore details)
• excellent 5
•good 4
•fair 3
•poor 2