Nortel VoIP Gateway, Configuration Manual

Page: 170 / 220

170 Silence compression on Full Duplex Links
P0606298 02
Silence compression on Full Duplex Links
On full duplex links, the transmit path and the receive path are separate channels, with bandwidths
usually quoted in terms of individual channels. The following figure shows the peak bandwidth
requirements for one call on a full-duplex link without silence compression. Voice packets are
transmitted, even when a speaker is silent. Therefore, the peak bandwidth and the average
bandwidth used equals the full transmission rate for both the transmit and the receive channel.
Figure 51 One call on a full duplex link without silence compression
Time ->
B
andwidth -
>
Tx
C
h
an
B
andw
idth -
>
Bandwidth Used
Voice frames sent even
Rx
Tx
Fred Here.
Hello Fred. This is Susan. Do you have a minute?
Time ->
Sure! Hi!
Rx
Ch
an
Channel Max
Channel Max
Hello Fred. This is Susan. Do you have a minute?
Fred here. Hi!
Sure!
Conversation
Bandwidth used
Voice frames sent even when speaker is silent
Time
Channel/Link max
Tx
c
h
a
n
n
e
l
B
a
ndw
id
th
Tx
Rx
Channel/Link max
Rx
c
h
a
n
n
e
l
Ba
nd
w
idt
h
Time