Nortel Networks NN43001-563 - page 148

148 ITG engineering guidelines
This model already takes into account some characteristics of the IP Phone,
and therefore the impairment factors are not identical to those shown in
the ITU-T standards.
Refer to Table32 "R value translation" (page 149) for the translation of R
values into user satisfaction levels.
Table 2 9
Impairment factors of codecs
Codec Codec Impairment (lc) (msec frames)
G.711 0
G.729A/AB 11 - 20 or 30
G.729A/AB 16 - 40 or 50
G.723.1 (5.3 Kbps) 19
G.723.1 (6.3 Kbps) 15
Table 3 0
Impairment factors due to network delay
Network delay* (msec) Delay Impairment (ld)
0 - 49 0
50 - 99 5
100 -149 10
150 - 199 15
200 - 249 20
250 - 299 25
* Network delay is the average one-way network delay plus packetization and
jitter buffer delay.
Table 3 1
Impairment factors due to packet loss
Packet loss (%) Packet Lose Impairment (lp)
00
14
28
415
825
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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