Nortel VoIP Gateway, Configuration Manual

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Silence Compression on Half Duplex Links 169
Norstar VoIP Gateway Configuration Guide
The effect of silence compression on half-duplex links is, therefore, to reduce the peak and average
bandwidth requirements by approximately 50% of the full transmission rate. Because the sender
and receiver are sharing the same bandwidth, this affect can be aggregated for a number of calls.
The following figure shows the peak bandwidth requirements for two calls on a half-duplex link
with silence compression enabled. The peak bandwidth for all calls is equal to the sum of the peak
bandwidth for each individual call. In this case, that is twice the full transmission rate for the two
calls.
Figure 50 Two calls on a half duplex link with silence compression
Time ->
Conversations
Bandwidth Used
Rx
Tx
Fred Here.
Hello Fred. This is Susan. Do you have a minute?
Sure! Hi!
Rx
Tx
Fred Here.
Hello Fred. This is Susan. Do you have a minute?
Sure! Hi!
B
andwi
d
th -
>
Tx
+
Rx Chan
Bandwidth shared by
“half-duplex” calls.
Rx
Tx
Hola Isabella!
Buenos noches Juan. Muy bien, y tu?
Como estas?
Rx
Tx
Hola Isabella!
Buenos noches Juan. Muy bien, y tu?
Como estas?
Peek channel bandwidth is
n * average bandwidth per call.
Channel/Link Max
Hello Fred. This is Susan.
Do you have a minute?
Conversation
Fred here.
Hi!
Sure!
Conversation
Bandwidth used
Peak channel bandwidth is n * average
bandwidth per call.
Time
Channel/Link max
Tx +
Rx Ch
an
Ba
nd
wi
dt
h
Tx
Rx
Tx
Rx
Buenos noches Juan
Muy bien, y tu?
Hola Isabella Com o estas?
Bandwidth shared by half-duplex calls