[SIPForum-discussion] Silence suppressionattribute basedonrfc3108

Sun Jul 12 03:05:22 UTC 2009

 As someone said earlier it is endpoint implementation . I recently used this attribute to turn off VAD when G.711 codes is used for fax communication. By default VAD is turned on and when this attribute is no more seen in SD, VAD will remain the same.  Original message From:Boris Vercher< boris.vercher at ilexia.com >Date: 09 July 09 13:58:05Subject:Re: [SIPForumdiscussion] Silence suppressionattributebasedonrfc3108To: "'Manpreet Singh'" , "'Spencer Dawkins'" , "'Andro'"Silence suppression is an option,by the way, if nothing is précised or if there are no attribute, silence suppression have to be removed De : discussionbounces at sipforum.org [mailto:discussionbounces at sipforum.org] De la part de Manpreet Singh Envoyé : mercredi 8 juillet 2009 20:29 À : Spencer Dawkins; Andro Cc : discussion at sipforum.org Objet : Re: [SIPForumdiscussion] Silence suppression attribute basedonrfc3108 Even thi RFC is not talking about default behaviour for absence of optional parameters like silence
  suppression. G729 is very clearly defined such that absence of anneb mean anneb=yes. What does absence of silencesuppression attribute imply? Thnx From: Spencer Dawkins [mailto:spencer at wonderhamster.org]Sent: Wednesday, July 08, 2009 12:00 PM To: Andro; Manpreet Singh Cc: discussion at sipforum.org Subject: Re: [SIPForumdiscussion] Silence suppression attribute basedonrfc3108this was identified as a common interworking problem in SIPconnect/1.1 discussions  there are implementations that don't realize that annexb is enabled by default. Spencer Original Message  From: Andro To: Manpreet Singh Cc: discussion at sipforum.org Sent: Tuesday, July 07, 2009 10:18 AMSubject: Re: [SIPForumdiscussion] Silence suppression attribute basedonrfc3108 Hello, I don't know if this answers your question, but I remember that , if annexb support is not specified in SDP payload , it is enabled by default for g729.Andrea2009/7/6 Manpreet Singh Not sure if its still clear. 3389 talks about paylaod defit
 ion for CN. Its not touching the case where silencesuppression attribute is there or not. May be I am missing the text in the RFC so if someone can point me to exact excerpt, would be helpful. But my question is still not answered well in these rfcs. 3389 does say one needs to define the payload type to support CN. Absence of this doesn't mean no CN but RTP can still handle it via noncontinous sequence numbers.The question really was if G729A or any other codec where Silence suppression is not ON by default, absence of silencesuppression attrbute in SDP means ON or OFF?Ofcourse if one says ON then the SDP needs to define CN payload. But would that mean abesence of silencesuppression attribute means no VAD?Thnx Original Message From: John Atkinson [mailto:johnat at nortel.com] Sent: Wednesday, July 01, 2009 8:24 PM To: Anuradha Prakashkumar; Manpreet Singh; discussion at sipforum.org Subject: RE: [SIPForumdiscussion] Silence suppression attribute based onrfc3108read RFC 3555 for 72
 9AnnexB useand 723annexA useand, as mentioned below, see rfc 3389 for codecs such as 711 and 72632 that don't have their own vad/cng/dtx algorithmsOriginal Message From: discussionbounces at sipforum.org [mailto:discussionbounces at sipforum.org] On Behalf Of Prakashkumar, Anuradha WIPRO (External:WBNG:WIPRO) Sent: Wednesday, July 01, 2009 12:52 AM To: msingh at ibasis.net; discussion at sipforum.org Subject: Re: [SIPForumdiscussion] Silence suppression attribute based onrfc3108RFC 3389? Have you checked? It talks lots about VAD and Noise level comfort. Also I could somewhere read it as endpoint implementation dependent. Will let you know if I get something more.From: Manpreet Singh [mailto:msingh at ibasis.net] Sent: Wednesday, July 01, 2009 9:34 AM To: Anuradha Prakash kumar (WT01  Telecom Equipment); discussion at sipforum.org Subject: RE: [SIPForumdiscussion] Silence suppression attribute based on rfc3108AnuradhaThanks for the URL. Although it does say default is ON, its not writen in any
  spec. Is there a reference to spec you can point me to? Alteast 3108 doesnt talk about this and I am not sure where they are taking that reference.thnxFrom: anuradha.kumar1 at wipro.com [mailto:anuradha.kumar1 at wipro.com] Sent: Tuesday, June 30, 2009 11:54 PM To: Manpreet Singh; discussion at sipforum.org Subject: RE: [SIPForumdiscussion] Silence suppression attribute based on rfc3108Hello Manpreet,I had a chance to look at this. VAD or silence suppression is used to save bandwidth in a case where the originating and terminating parties do not speak but still thevoice gets played which is unnecessary.Now coming to your question whenever not indicated silence suppression or Voice Activity Detection is set to ON. I guess we can verify this as well by monitoring it by network analyzers like wire shark. Please refer to the URL https://lists.cs.columbia.edu/pipermail/sipimplementors/2006January/01 1717.htmlRegards,AnuFrom: discussionbounces at sipforum.org [mailto:discussionbounces at sipfor
 um.org] On Behalf Of Manpreet Singh Sent: Tuesday, June 30, 2009 9:06 PM To: discussion at sipforum.org Subject: [SIPForumdiscussion] Silence suppression attribute based on rfc3108HiIf the silence suppression attribute is not present in SDP, whats the default behaviour? Would the absence mean ON or OFF for a certain media type?thnxPlease do not print this email unless it is absolutely necessary.The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this email. Please notify the sender immediately and destroy all copies of this message and any attachments.WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any dam
 age caused by any virus transmitted by this email.www.wipro.com  This is the SIP Forum discussion mailing list TO UNSUBSCRIBE, or edit your delivery options, please visit http://sipforum.org/mailman/listinfo/discussion Post to the list at discussion at sipforum.org  This is the SIP Forum discussion mailing list TO UNSUBSCRIBE, or edit your delivery options, please visit http://sipforum.org/mailman/listinfo/discussion Post to the list at discussion at sipforum.org 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://sipforum.org/pipermail/discussion/attachments/20090712/c1e74e85/attachment.html