Re: [Dart] Treatment of RTCP - proposed text
"Paul E. Jones" <paulej@packetizer.com> Thu, 28 August 2014 03:20 UTC
Return-Path: <paulej@packetizer.com>
X-Original-To: dart@ietfa.amsl.com
Delivered-To: dart@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 60C631A0307; Wed, 27 Aug 2014 20:20:52 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.66
X-Spam-Level:
X-Spam-Status: No, score=-1.66 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_ADSP_ALL=0.8, DKIM_SIGNED=0.1, RP_MATCHES_RCVD=-0.668, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_DKIM_INVALID=0.01] autolearn=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZSOnnmZ2suxk; Wed, 27 Aug 2014 20:20:51 -0700 (PDT)
Received: from dublin.packetizer.com (dublin.packetizer.com [75.101.130.125]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 009231A030B; Wed, 27 Aug 2014 20:20:50 -0700 (PDT)
Received: from [192.168.1.20] (cpe-024-211-197-136.nc.res.rr.com [24.211.197.136]) (authenticated bits=0) by dublin.packetizer.com (8.14.5/8.14.5) with ESMTP id s7S3Kijg003277 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Wed, 27 Aug 2014 23:20:44 -0400
DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=packetizer.com; s=dublin; t=1409196044; bh=c545PER2LlmyNwPZamqivmOmFXeq5F51xWjDCn6YMNc=; h=From:To:Subject:Cc:Date:Message-Id:In-Reply-To:Reply-To: Mime-Version:Content-Type:Content-Transfer-Encoding; b=l6Rn9v/Ux1K57vqV6ogQYJYnV/2Su4DWRG5Iboaf6Eu9DvSGDb0x1196DYYrENCZX CCruRtItsUF5MhQQPwylHqgMDwhibjhmFn3xYmsV/Cr4NpiYN6xTQKEhOvkH0L9wHL NFWvDD2dSqhpIQGMWdFuDRvxpZj0SHU3geb5arhs=
From: "Paul E. Jones" <paulej@packetizer.com>
To: Ben Campbell <ben@nostrum.com>, "Black, David" <david.black@emc.com>
Date: Thu, 28 Aug 2014 03:21:13 +0000
Message-Id: <em14e0cabb-7036-4655-aa40-a3f72b83f433@sydney>
In-Reply-To: <B6DC0D42-4F86-4BCA-BD76-48C3A0FFBB83@nostrum.com>
User-Agent: eM_Client/6.0.20617.0
Mime-Version: 1.0
Content-Type: text/plain; format="flowed"; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: http://mailarchive.ietf.org/arch/msg/dart/s4M7eVhu3E5J_e5aAvc8fGmDbSw
Cc: "draft-ietf-dart-dscp-rtp.all@tools.ietf.org" <draft-ietf-dart-dscp-rtp.all@tools.ietf.org>, "dart@ietf.org" <dart@ietf.org>, Colin Perkins <csp@csperkins.org>, Michael Welzl <michawe@ifi.uio.no>, "avt@ietf.org WG" <avt@ietf.org>
Subject: Re: [Dart] Treatment of RTCP - proposed text
X-BeenThere: dart@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
Reply-To: "Paul E. Jones" <paulej@packetizer.com>
List-Id: "\"DiffServ Applied to RTP Transports discussion list\"" <dart.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dart>, <mailto:dart-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/dart/>
List-Post: <mailto:dart@ietf.org>
List-Help: <mailto:dart-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dart>, <mailto:dart-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 28 Aug 2014 03:20:52 -0000
Ben, I think the answer is really whether we can quickly reach consensus. I have an idea how I'd implement it if I didn't have guidance otherwise, which I explained in my last email. I think this can be resolved pretty quickly. If not, we can certainly leave it open. Paul ------ Original Message ------ From: "Ben Campbell" <ben@nostrum.com> To: "Black, David" <david.black@emc.com> Cc: "Paul E. Jones" <paulej@packetizer.com>; "Michael Welzl" <michawe@ifi.uio.no>; "Colin Perkins" <csp@csperkins.org>; "draft-ietf-dart-dscp-rtp.all@tools.ietf.org" <draft-ietf-dart-dscp-rtp.all@tools.ietf.org>; "dart@ietf.org" <dart@ietf.org>; "avt@ietf.org WG" <avt@ietf.org> Sent: 8/27/2014 10:28:07 PM Subject: Re: Treatment of RTCP - proposed text >I do not object to the text per se. > >But I do have a bit of a nagging concern that we may be offering too >strong of guidance, given the thought process so far. Do we believe we >understand this well enough to say the sender should to this or that, >as opposed to say that these are things the implementer should think >about, and that these are probably reasonable choices? > >Is this an area where we need more deployment experience to offer real >guidance? (I think it's okay for the doc to say that, if needed.) > >But in any case, I will defer to Colin, Paul, and David. > >On Aug 27, 2014, at 8:58 PM, Black, David <david.black@emc.com> wrote: > >> Trying to propose some text here: >> >> OLD >> o Should use a single DSCP for an RTCP session, primarily to avoid >> RTCP reordering (and because there is no compelling reason for >>use >> of different drop precedences). One of the PHBs and associated >> DSCP used for the associated RTP traffic would be an appropriate >> choice. [Editor's note: This bullet is an open technical issue.] >> NEW >> o Should use the same DSCP for RTCP reports as used for the RTP >>stream >> that is being reported on when that DSCP is known by the RTCP >>sender. >> When an RTP stream uses multiple DSCPs that differ only in drop >> precedence, RTCP reports on that RTP stream should use the DSCP >>with >> the least likelihood of drop to favor delivery of the RTCP >>reports. >> When a single RTCP message reports on multiple RTP streams that >> are sent with different DSCPs, the RTCP sender should choose one >> of those DSCPs. When the RTCP sender does not know what >> DSCP or DSCPs were used to send an RTP stream, it should choose >> a DSCP that it would use to send a similar RTP stream. >> >> The latter sentence is courtesy of the fact that there will be cases >> where the RTCP sender will not know what DSCP or DSCPs were used to >>send >> the RTP stream, due to en-route remarking. >> >> If that text looks close, I'll edit further and try to get the -05 >>submitted >> by the end of this week. >> >> Thanks, >> --David >> >>> -----Original Message----- >>> From: Paul E. Jones [mailto:paulej@packetizer.com] >>> Sent: Wednesday, August 27, 2014 6:53 PM >>> To: Ben Campbell; Michael Welzl; Colin Perkins; Black, David >>> Cc: draft-ietf-dart-dscp-rtp.all@tools.ietf.org; dart@ietf.org; >>>avt@ietf.org >>> WG >>> Subject: Re: [Dart] [AVTCORE] Treatment of RTCP (was Re: Colin >>>Perkins >>> comments - WGLC: draft-ietf-dart-dscp-rtp-02) >>> >>> RTCP might not be used for RTT calculations (it might; I just doubt >>>it's >>> terribly useful), but RTCP might be used to convey QoE measurements >>>or >>> one-way delay information useful for RMCAT. >>> >>> I think there is agreement that the DSCP value applied to the RTCP >>> packet for a given SSRC sender should align with the DSCP value used >>>for >>> the corresponding RTP packets of that sender. In the case where an >>>AFxx >>> class is used, I'm not sure there is agreement (though no >>>disagreement). >>> I stated my view that we should use the lowest drop precedence in >>>that >>> case, but others should weigh in. >>> >>> Paul >>> >>> ------ Original Message ------ >>> From: "Ben Campbell" <ben@nostrum.com> >>> To: "Michael Welzl" <michawe@ifi.uio.no>; "Colin Perkins" >>> <csp@csperkins.org>; "Paul E. Jones" <paulej@packetizer.com>; >>>"Black, >>> David" <david.black@emc.com> >>> Cc: "draft-ietf-dart-dscp-rtp.all@tools.ietf.org" >>> <draft-ietf-dart-dscp-rtp.all@tools.ietf.org>; "dart@ietf.org" >>> <dart@ietf.org>; "avt@ietf.org WG" <avt@ietf.org> >>> Sent: 8/27/2014 4:48:37 PM >>> Subject: Re: [Dart] [AVTCORE] Treatment of RTCP (was Re: Colin >>>Perkins >>> comments - WGLC: draft-ietf-dart-dscp-rtp-02) >>> >>>> On Aug 27, 2014, at 3:45 PM, Michael Welzl <michawe@ifi.uio.no> >>>>wrote: >>>> >>>>> I don't know the beginning of this but I can help go up the stack: >>>>> >>>>> for the short dialogue between Colin and me, the conclusion is: >>>>>Colin >>>>> is right. RTCP probably won't be used by congestion control to >>>>> estimate the RTT. >>>>> >>>> >>>> Thanks, Michael, I think that fits with some earlier conversations >>>>as >>>> well. >>>> >>>> Colin and Paul (and David): >>>> >>>> Are we converging on what guidance to put into the DART draft? >>>> >>>> Thanks! >>>> >>>> Ben. >>>> >>>> >>>> _______________________________________________ >>>> Dart mailing list >>>> Dart@ietf.org >>>> https://www.ietf.org/mailman/listinfo/dart >> >
- [Dart] Treatment of RTCP - proposed text Black, David
- Re: [Dart] Treatment of RTCP - proposed text Ben Campbell
- Re: [Dart] Treatment of RTCP - proposed text Paul E. Jones
- Re: [Dart] Treatment of RTCP - proposed text Paul E. Jones
- Re: [Dart] Treatment of RTCP - proposed text Black, David
- Re: [Dart] Treatment of RTCP - proposed text Colin Perkins