Server User Manual

150 ITG engineering guidelines
QoS level
Network
delay (ms)
Packet
loss (%)
G.711
20
G.729A/AB
30
G.723.1 (6.3 Kbps)
30
199 1
fair
poor
good
199 2
fair
poor
fair
199 4
poor
not recommended not recommended
199 8
not recommended not recommended not recommended
200 – 249 0
poor
not recommended not recommended
249 1
poor
not recommended not recommended
249 2
poor
not recommended not recommended
249 4
not recommended not recommended not recommended
249 8
not recommended not recommended not recommended
250 – 299 0
poor
not recommended not recommended
299 1
poor
not recommended not recommended
299 2
poor
not recommended not recommended
299 4
not recommended not recommended not recommended
299 8
not recommended not recommended not recommended
The QoS levels are equivalent to the following MOS values: See "E-Model" (page
73) for more details.
•
excellent 4.5
•
good 4
•
fair 3
• poor 2
•
not recommended less than 2
Sample scenarios
Scenario 1 A local LAN has the following characteristics:
•
G.711 codec
•
20 msec network delay
•
0.5% packet loss
To calculate R = 94 - lc - ld - lp, use Table 29 "Impairment factors of codecs"
(page 148), Table 30 "Impairment factors due to network delay" (page 148),
and Table 31 "Impair ment factors due to packet loss" (page 148):
•
G.711 codec: lc = 0
•
20 msec network delay: ld = 0
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
Copyright © 2007, Nortel Networks
.