RE: [AVT] draft-ietf-avt-rtp-cn-06
"Fairlie-Cuninghame, Robert" <rfairlie@nuera.com> Mon, 17 June 2002 20:38 UTC
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From: "Fairlie-Cuninghame, Robert" <rfairlie@nuera.com>
To: "'Campos, Simao'" <simao.campos@itu.int>, "'avt@ietf.org'" <avt@ietf.org>
Subject: RE: [AVT] draft-ietf-avt-rtp-cn-06
Date: Mon, 17 Jun 2002 13:39:14 -0700
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Hi Simao, > I see your point but please keep in mind that a mandatory > minimum rate might > break interoperability scenarios (say PSTN->VoIP->PSTN) if the systems > outside the IP network behave differently from a "mandatory" setup. > Additionally, this issue is very system-specific and I am not > aware of a > well-accept threshold for it; some systems use every 5 > seconds, others every > 20s... It might be hard to nail down a number. Even a large period of 20 secs would provide some useful properties. I am doubtful that many RTP over UDP implementations would use a value this large. Even sending a SID packet every 5 seconds is not going cause excessive network traffic. I understand the backwards compatibility issues but I would be interested to find out just how many systems supporting CN today (over unreliable transport protocols) really don't transmit every a SID packet at least as often as an RTCP retransmit period, say 5-10 seconds. CN is still only a draft. Requiring a minimum retransmission period over unreliable transport would have significant benefits and I'm not convinced it would break any reasonable implementations today. > This might be a parameter negotiated/communicated at session > establishment, > so both ends would know what to expect and adjust accordingly. I'm sure it could but it really doesn't need to be - its yet another parameter to be negotiated. Hey can we get an acronym for that? YAPTBN? :) Robert. > Best regards, > Simao > > > -----Original Message----- > > From: Fairlie-Cuninghame, Robert [mailto:rfairlie@nuera.com] > > Sent: 11 June 2002 18:57 > > To: 'avt@ietf.org' > > Subject: [AVT] draft-ietf-avt-rtp-cn-06 > > > > > > Hi, > > > > The current incarnation of the draft says: > > > > The CN packet update rate is left implementation > > specific. For example, the CN packet may be sent > periodically or > > only when there is a significant change in the background noise > > characteristics. > > > > The latter scheme is undesirable when the transport is > > unreliable (as most > > RTP currently is). Shouldn't the draft recommend a minimum > > update period? > > This would also be beneficial given that endpoints may also > > rely on period > > comfort noise packets for keeping firewall holes open, it > > would be nice if > > there was a recommendation that they should be sent AT LEAST > > every so often. > > > > Regards, > > > > Robert. > > > > _______________________________________________ > > Audio/Video Transport Working Group > > avt@ietf.org > > https://www1.ietf.org/mailman/listinfo/avt > > > _______________________________________________ Audio/Video Transport Working Group avt@ietf.org https://www1.ietf.org/mailman/listinfo/avt
- [AVT] draft-ietf-avt-rtp-cn-06 Fairlie-Cuninghame, Robert
- RE: [AVT] draft-ietf-avt-rtp-cn-06 Campos, Simao
- RE: [AVT] draft-ietf-avt-rtp-cn-06 Fairlie-Cuninghame, Robert
- [AVT] draft-ietf-avt-rtp-cn-06 Oren Peleg
- RE: [AVT] draft-ietf-avt-rtp-cn-06 Robert Zopf