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320 channels of V.32 SPRT

The above channel counts are the same if AES encryption and SHA-1 authentication are 
enabled.
The One-X Deskphones (96xx) support the G.722 codec with 64 kbps and with 20 ms packets
Generally, G.711 is used on LANs because bandwidth is abundant and inexpensive whereas 
G.729 is used across bandwidth-limited WAN links.

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:

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 trade-off with 
silence suppression lies with the silence detection algorithm. If it is too aggressive, the 
beginnings and ends of words can be "clipped." If not aggressive enough, no bandwidth is 
saved. 
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:

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Avaya Communication Manager software (for control)

G.726A Unencrypted

10

16

32

G.726A with AEA Encryption

10

16

32

G.726A with AES Encryption

10

12

24