IETF Logo Mail Archive

Re: [rtcweb] SDP_PRANSWER followed by SDP_OFFER scenario in JSEP

Neil Stratford <neils@belltower.co.uk> Fri, 11 May 2012 15:04 UTC

Return-Path: <neils@vipadia.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 55B9D21F84B6 for <rtcweb@ietfa.amsl.com>; Fri, 11 May 2012 08:04:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.599
X-Spam-Level:
X-Spam-Status: No, score=-3.599 tagged_above=-999 required=5 tests=[AWL=0.001, BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id X5PnEUykAESB for <rtcweb@ietfa.amsl.com>; Fri, 11 May 2012 08:04:36 -0700 (PDT)
Received: from mail-wi0-f172.google.com (mail-wi0-f172.google.com [209.85.212.172]) by ietfa.amsl.com (Postfix) with ESMTP id 98A8921F84B2 for <rtcweb@ietf.org>; Fri, 11 May 2012 08:04:36 -0700 (PDT)
Received: by wibhr2 with SMTP id hr2so1496070wib.13 for <rtcweb@ietf.org>; Fri, 11 May 2012 08:04:35 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=sender:subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer :x-gm-message-state; bh=JgPo6piXXnp3hUTihnNaJRlL++2b3uUrXNM8E5DeqMQ=; b=WXKTuHUCIFPN1JdzAVBxP505VUnRSprgrmI6pdQG/GDNSA2BnVtxRsOoyrkAL1LYq4 nGcrs/ike1egK/Yld+GoiEOWRZnEvpVpogiqxpp8IunZd+HRpQT91jARI4gIDhULuOmL h+bxCGHHPfw9dqsZgsFkjKKmJkaE146AKIXd49uP4RRx+lIG2N8HTYeb/RUtr2XSluLB ZGAINxE3ONcx7y4IgkKHIfCKxNsZt7/IDwZs0ezHsxMXZY6uAtHiMxXyn/rVXBZbVBpD T/FlqodOLRIGMXHrKtfPFC/aFyA8+q2Gt39SXQews+dQw8eqFm0v02mSh8MXSX0uZ0A8 2Exw==
Received: by 10.180.82.136 with SMTP id i8mr8482650wiy.19.1336748675608; Fri, 11 May 2012 08:04:35 -0700 (PDT)
Received: from [192.168.0.117] ([82.152.81.57]) by mx.google.com with ESMTPS id gd4sm17933064wib.6.2012.05.11.08.04.32 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 11 May 2012 08:04:34 -0700 (PDT)
Sender: Neil Stratford <neils@vipadia.com>
Mime-Version: 1.0 (Apple Message framework v1257)
Content-Type: text/plain; charset="us-ascii"
From: Neil Stratford <neils@belltower.co.uk>
In-Reply-To: <6F428EFD2B8C2F49A2FB1317291A76C1136D546819@USNAVSXCHMBSA1.ndc.alcatel-lucent.com>
Date: Fri, 11 May 2012 16:04:31 +0100
Content-Transfer-Encoding: quoted-printable
Message-Id: <6BF70DE5-5C59-4B64-BAFC-394E7BBF9442@belltower.co.uk>
References: <387F9047F55E8C42850AD6B3A7A03C6C0E23B102@inba-mail01.sonusnet.com> <6F428EFD2B8C2F49A2FB1317291A76C1136029362A@USNAVSXCHMBSA1.ndc.alcatel-lucent.com> <4FA13816.6050003@alvestrand.no> <CAD5OKxsOAeTRdCgj2g4BY8maeG1n9nzCv29g8kaFPVZ4tf8C5w@mail.gmail.com> <4FA15898.1040204@alvestrand.no> <7F2072F1E0DE894DA4B517B93C6A05852C44001329@ESESSCMS0356.eemea.ericsson.se> <CAD5OKxsbTSpMPg30P4DSN6UasCx6na43tpZ5yT2ct6SLMpd9xQ@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A05852C4400132C@ESESSCMS0356.eemea.ericsson.se> <6F428EFD2B8C2F49A2FB1317291A76C1136047B753@USNAVSXCHMBSA1.ndc.alcatel-lucent.com> <7F2072F1E0DE894DA4B517B93C6A05852C4400132F@ESESSCMS0356.eemea.ericsson.se> <CAD5OKxuy8_Ras3X-8tcY1qaLRTVJ-z-JuXQaf0NKaRwN_dU18Q@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A05852C442AC0DA@ESESSCMS0356.eemea.ericsson.se> <CAD5OKxuv7T6YrEXEeVECKbGtRg4feoRYTgvC57yqWXTBK43ypg@mail.gmail.com> <4FA2B447.7010504@jesup.org> <4FA2E264.4040207@jesup.org> <7F2072F1E0DE894DA4B517B93C6A05852C44001 338@ESESSCMS0356.eemea.ericsson.se> <CAD5OKxuq14_DfSJuFEHq_ZEubbOYt7NFTcXWpLND8ggAr37QhA@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A05852C44001339@ESESSCMS0356.eemea.ericsson.se> <CAD5OKxvFYy-9XAE5GG0n58xX2HKRX3o5qkTZ2o6rugakaM77Ew@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A05852C4400133A@ESESSCMS0356.eemea.ericsson.se> <CAOJ7v-1Ue=q4MAh0csiDLvRFfMGaJ4vWrDxhir-S-OjSTsymaw@mail.gmail.com> <387F9047F55E8C42850AD6B3A7A03C6C160337F1@inba-mail01.sonusnet.com> <6E35F409-3B3F-4D92-91F2-451E0910CFDE@iii.ca> <CABkgnnVO5UyhHjiWVPsLYAoXSKPsfn6Fnb10hQr_6-kgq0FC3g@mail.gmail.com> <F0D1114C-0B6C-4AED-BDD3-4E3D6A219485@iii.ca> <CABkgnnWNLOb_xLUfOoZ5d7sKVsJDvjmNhmRqFcupO4S4p8Nrfw@mail.gmail.com> <219EC9F7-87B8-4E7B-8D6F-58A5B9773D29@iii.ca> <6F428EFD2B8C2F49A2FB1317291A76C1136D546819@USNAVSXCHMBSA1.ndc.alcatel-lucent.com>
To: "Ejzak, Richard P (Richard)" <richard.ejzak@alcatel-lucent.com>
X-Mailer: Apple Mail (2.1257)
X-Gm-Message-State: ALoCoQmyzigAdXvszDOq2tX8gHO4hqe6RhZM4E4HA00Os546i2LB1DRzT7dLJzvG85aRbXNeSZWs
Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] SDP_PRANSWER followed by SDP_OFFER scenario in JSEP
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 11 May 2012 15:04:37 -0000

On 11 May 2012, at 15:26, Ejzak, Richard P (Richard) wrote:

> But things are different with ICE and DTLS, particularly if you want to avoid media intermediaries.  Significant clipping is a real possibility if we have to restart ICE/DTLS after the "winner" responds with 200 OK.
> 
> This is not a separate use case, but a given aspect of interworking with SIP.

The whole problem of clipping audio due to the delay between the 200OK and the media actually flowing raises a flag that we are triggering upper layers of the stack on the wrong event. 

Why is anyone sending media before the media channel is fully established? Why tell the user (or IVR etc) that the call is answered before we have a working media channel?

Neil

v2.23.0 | Report a Bug | By Email