Silence suppression/VAD
●320 channels of V.32 SPRT
The above channel counts are the same if AES encryption and
The
Generally, G.711 is used on LANs because bandwidth is abundant and inexpensive whereas G.729 is used across
G.726 Codec and H.248 Media Gateways
As of Communication Manager release 3.1, media processing resources on H.248 Media Gateways support the G.726 codec. The following table provides the corresponding capacities:
Table 47: Number of Simultaneous
Codec | G250 | G350 | G700 |
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G.726A Unencrypted | 10 | 16 | 32 |
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G.726A with AEA Encryption | 10 | 16 | 32 |
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G.726A with AES Encryption | 10 | 12 | 24 |
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Silence suppression/VAD
Voice Activity Detection (VAD) or silence suppression can also be used to save bandwidth. During a conversation, because only one party is speaking at any given time, more than 40% of the transmission is silence. Voice Activity Detection (VAD) in Avaya IP telephones monitor the locally produced voice signal for voice activity. When no activity is detected for the configured period of time, packets are no longer transmitted. This prevents the encoder output from being transported across the network when there is silence, resulting in bandwidth savings.
When silence suppression is enabled, the remote end is instructed to generate "comfort noise" when no voice is present to make the call sound more natural to users. The
Silence suppression is built into G.729B. It can be enabled for other codecs from within Communication Manager. Because of voice quality concerns with respect to clipping, silence suppression is generally disabled (with the exception of G.729B).
The following Avaya products employ silence suppression to preserve bandwidth:
●Avaya Communication Manager software (for control)
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