Comfort noise support incomplete in Asterisk (RFC 3389)

11.5.3.3. Comfort noise support incomplete in Asterisk (RFC 3389)

NOTICE[4537]: rtp.c:330 process_rfc3389: Comfort noise support incomplete in Asterisk (RFC 3389). Please turn off on client if possible. Client IP: x.x.x.x

1. Explanation:

Asterisk does not (yet) support voice activity detection (and comfort noise generation).

Voice activity detection is when a softphone or hardphone tries to detect if the speaker is silent, and will send no audio packets for that time. (to save on bandwidth).

As this might sound unnatural for the other party of the call, if no background noise is sent. (it would sound like a walkie talkie)

That is why a PBX or the other phone could generate comfort noise, which is simulated noise to make the call sound more natural.

Asterisk does not support VAD and thus also does not support the generation of comfort noise.

The best thing to do for now, is to completely disable Voice activity detection on the clients connected to asterisk.

On recent asterisk versions, asterisk will tell you the ip of the phone sending those packets. You really want to disable it as it will flood you asterisk server and generate bad quality audio.

2. Howto disable this VAD thing on different sip and h323 phones.

- In Idefisk 2.0 this is called "transmit silence"
- on eyebeam this is called enable VAD. (under media -> audio -> devices).

(if you know how to disable this on other phones, please post a comment!.)

User Comments

karim (karim dot gillani at gmail dot com)
13 June 2008 05:45:02
how do you disable for linksys pap2?

YOGESH BHARDWAJ (yogesh at swissfoneindia dot net)
15 January 2008 13:19:19
How to disable VAD in asterisk server

Marco (marco at cyberhq dot nl)
18 December 2007 15:27:24
Cisco 7905/1912:

Set the last bit of the AudioMode parameter to 0. To keep the other settting default, this would do:

AudioMode:0x00000010

dvg (dvg at guru dot com)
04 October 2007 21:10:46
On the DLink DVG-2001S, VAD can be disabled in the Telephony section of the Advanced VoIP configuration in the http://<ip>/admin menu.

kyriakos (kyriakos at otenet-telecom dot com)
18 September 2007 15:53:05
On 7960/40 include:
"enable_vad: "0"
in SIPDefault.conf.
This should disable VAD on all 7960/40 phones.

Enrico (enrico dot durani at areaweb dot it)
02 October 2006 15:19:33
How to disable VAD on Cisco 7905?

Thanx

Roel van Meer (rolek at alt001 dot com)
21 September 2006 14:45:27
For Thomson ST2030 phones, VAD can be disabled in the administration interface, under Advanced, Voice Settings, Advanced.

Redouane (redouane dot doumer at actimagine dot com)
07 August 2006 14:26:51
How to disable it idefisk?

Redouane

Roberto Braga (roberto at talktelecom dot com dot br)
08 May 2006 18:07:43
Hi. There will be any chances of this be implemented on Asterisk in a near future?
If no, I am interested on doing it, if there is any work in progress please send me any references so I can continue working on it.
Regards.

Eason (eason at weltech dot com)
13 April 2006 10:57:43
In Welltech FXO device, please disable the VAD function by [sysconf -silence 0].

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