Re: [rtcweb] JSEP: Relaxing SDP O/A rules?

Christer Holmberg <christer.holmberg@ericsson.com> Fri, 05 October 2012 21:31 UTC

Return-Path: <christer.holmberg@ericsson.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 5450521F8692 for <rtcweb@ietfa.amsl.com>; Fri, 5 Oct 2012 14:31:03 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.101
X-Spam-Level:
X-Spam-Status: No, score=-6.101 tagged_above=-999 required=5 tests=[AWL=0.148, BAYES_00=-2.599, HELO_EQ_SE=0.35, RCVD_IN_DNSWL_MED=-4]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id axxYol4gx2m3 for <rtcweb@ietfa.amsl.com>; Fri, 5 Oct 2012 14:31:02 -0700 (PDT)
Received: from mailgw2.ericsson.se (mailgw2.ericsson.se [193.180.251.37]) by ietfa.amsl.com (Postfix) with ESMTP id 501B021F864A for <rtcweb@ietf.org>; Fri, 5 Oct 2012 14:31:02 -0700 (PDT)
X-AuditID: c1b4fb25-b7f046d00000644c-a5-506f5195ae49
Received: from esessmw0191.eemea.ericsson.se (Unknown_Domain [153.88.253.125]) by mailgw2.ericsson.se (Symantec Mail Security) with SMTP id 69.C6.25676.5915F605; Fri, 5 Oct 2012 23:31:01 +0200 (CEST)
Received: from ESESSCMS0356.eemea.ericsson.se ([169.254.1.99]) by esessmw0191.eemea.ericsson.se ([153.88.115.84]) with mapi; Fri, 5 Oct 2012 23:31:00 +0200
From: Christer Holmberg <christer.holmberg@ericsson.com>
To: Martin Thomson <martin.thomson@gmail.com>
Date: Fri, 5 Oct 2012 23:26:59 +0200
Thread-Topic: [rtcweb] JSEP: Relaxing SDP O/A rules?
Thread-Index: Ac2jHNmSiGoPoyvRSteGrpcBNsQtAgAI03ch
Message-ID: <7F2072F1E0DE894DA4B517B93C6A05853409FF2FE5@ESESSCMS0356.eemea.ericsson.se>
References: <7F2072F1E0DE894DA4B517B93C6A0585340A1E3AB1@ESESSCMS0356.eemea.ericsson.se> <CABkgnnUFvw_J2+tvVBoHrzR9ZRkPT-6LhXvbaz_U1P7gqtJ4xw@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A0585340A7BC848@ESESSCMS0356.eemea.ericsson.se> <CABkgnnV6NcTeh=L_fpkpLv5UpkUSuacmQUtYwNKKwAfcb5+JQA@mail.gmail.com> <506D4F7A.5020109@alvestrand.no> <CABkgnnUgHRw4dtihk2fZppmzVWuV4hpvWtXt70N1HWQpJ+KsZw@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A05853409FF2FDF@ESESSCMS0356.eemea.ericsson.se> <CABkgnnV+jHWF3t8s3t37pbQyXJEP9N_MyHWd3SsfoNrhMU=NXw@mail.gmail.com> <7F2072F1E0DE894DA4B517B93C6A0585340A7BD0C5@ESESSCMS0356.eemea.ericsson.se>, <CABkgnnVFWDroiTWVOm6F3FRQ6dDkRjKdyV8apRK=0Y_ReYtmPA@mail.gmail.com>
In-Reply-To: <CABkgnnVFWDroiTWVOm6F3FRQ6dDkRjKdyV8apRK=0Y_ReYtmPA@mail.gmail.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
acceptlanguage: en-US
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrILMWRmVeSWpSXmKPExsUyM+Jvre7UwPwAg0m7ZS2O9XWxWVw784/R Yu2/dnYHZo8rE66weuycdZfdY8mSn0wBzFFcNimpOZllqUX6dglcGRPe72AueMZZ0b/PuoHx MnsXIyeHhICJxMrTR6FsMYkL99azgdhCAqcYJd7djOxi5AKy5zNK3Gq8BFTEwcEmYCHR/U8b pEZEQFdi0dkHYL3MAsESvV2TWUFsFgEVibnb54HZwgLGEp2fjzFB1JtIrNmxhgXCNpK4Om8J mM0rEC4x4cVPVohdR1klfh/8CdbAKRAosam1gRHEZgQ67vupNUwQy8Qlbj2ZzwRxtIDEkj3n mSFsUYmXj/+xQtSLStxpX88IUa8jsWD3JzYIW1ti2cLXzBCLBSVOznzCMoFRbBaSsbOQtMxC 0jILScsCRpZVjMK5iZk56eVGeqlFmcnFxfl5esWpmxiB0XRwy2/VHYx3zokcYpTmYFES57Xe usdfSCA9sSQ1OzW1ILUovqg0J7X4ECMTB6dUA2PG+kntR99vXjhTfzlzWp38mh/7trNvU9ec Wfab8xOXma5E5sonZz0fHu6av/9x8Laidx7LvOy2ixm4pAb2x52cevbHupUbuHaIiH/kuZnz 8riUXOfUf295CztWL392SWW27dkitt9JSdOc3Cv2/fCRTZlqnbm4yMgxNeC8Z0WLwwGlHVz3 /ixRYinOSDTUYi4qTgQA6RGWd3QCAAA=
Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] JSEP: Relaxing SDP O/A rules?
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, 05 Oct 2012 21:31:03 -0000

Hi,

>>>> If you want to support parallel forking, you need to be able to simultanously perform ICE etc with all remote peers.
>>>
>>> Right.  You can almost get that by pretending that it's just one
>>> remote peer with lots of candidates.  You can at least get to the
>>> consent point by doing that.  But you aren't going to nominate more
>>> than one pair.  Similarly, this will only generate a single DTLS
>>> session.
>>
>> I was thinking about the same once, but I think I found some issues (unfortunately they don't come to my mind at the moment).
>
> It's probably not going to be flawless, true.  As you say, media would
> be a little crazy.  You might be able to get one media stream out of
> it - not multiple.

And, I guess it would still require to be able to update the answer, as additional early dialogs (with associated remote ICE candidates) may be created.

>> Can I use the same local descriptor for every setLocal() call?
>
> My experience suggests that you can.  However, that's not stipulated
> in the API specification, so it's not an ironclad guarantee.

If it doesn't, and a new local descripor is created, you would need to send that one to the remote endpoint.

Regards,

Christer