Re: [rtcweb] JSEP-06: How to create the second offer where only the port numbers are changed?

Justin Uberti <juberti@google.com> Mon, 03 March 2014 14:39 UTC

Return-Path: <juberti@google.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A2BA11A01B3 for <rtcweb@ietfa.amsl.com>; Mon, 3 Mar 2014 06:39:28 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.925
X-Spam-Level:
X-Spam-Status: No, score=-1.925 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RP_MATCHES_RCVD=-0.547, SPF_PASS=-0.001] autolearn=ham
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 JPqNmM78GIVM for <rtcweb@ietfa.amsl.com>; Mon, 3 Mar 2014 06:39:26 -0800 (PST)
Received: from mail-vc0-x236.google.com (mail-vc0-x236.google.com [IPv6:2607:f8b0:400c:c03::236]) by ietfa.amsl.com (Postfix) with ESMTP id B25821A01E8 for <rtcweb@ietf.org>; Mon, 3 Mar 2014 06:39:25 -0800 (PST)
Received: by mail-vc0-f182.google.com with SMTP id id10so3618423vcb.41 for <rtcweb@ietf.org>; Mon, 03 Mar 2014 06:39:22 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=AFgDNnaNTEsFfThlUNKL20PGrEnGpgDZ87zecmF0UIU=; b=JCZkvgwdcwSSqfXIYw9C5nTmmYtCbwlFz1i6/jZvXSZkhC+AfqTncvAnQ+FAudw2yj BLrZHSsTePBXf5kN0VgOdCHA0Z4Caa1A3FL/zhbR8As1Uh3jVwjJU7UDsMPOlvVBUNnA T6sbWAWSqt1JmddiPlhDVm4viF7ACSdrevz8CSzF54aQVJOQ1/ryOx02mfjGFmLPW2mQ tu1UaW/5ZGISeOt7mwcOt3hB67bu90oc/L071LDpvS02KA5Sa8HT7Ycn+BUxsy1b+usN fgz4RDOtCBloLV/YNMZ0G7MpqHzLHK24XgTQ6LXehSZn/nBqhTVSN8et4rCzuR4lszX4 z5kg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type; bh=AFgDNnaNTEsFfThlUNKL20PGrEnGpgDZ87zecmF0UIU=; b=LdYtVAI/v3xvHiHya6fn7VHPjNaLlB1jDHQCHiJCyy88fiQ1uMIWdVIrBwzOIhc3dg sGXo7Zvn55t1UVuTipdKHb2zK7MuP75slmyCf84n+3drSZQsJcKPb8HeGFbhSfKqd53u JaPQc6aRUr/Mf9FC7pfPc1CZL9UAtM6KN+Cc3MucEIZsp4dymVVKDHIZZjiX5ZjinWXC XCpucvRsuJXeFp0+PneoSekBDFOTgzRPiPGPzMLC8UKbJkZluhOvzPKew52LBYqvoGB6 N7o36qJK5S1CYIwf4QFKI4GVTxeMSUEsSIcV8W5aBXr/QhbqdIor/clyd7RMuFPV9eyp mj7g==
X-Gm-Message-State: ALoCoQnQE7sh5c+3rauHj4rHBNc7w6U8rJ0V3PDu8SoQQ+TcAGeyEuvQhNiQBuuO3HX7xaIe4pUHVM7GO4RnATgM1RqZz6v5D59b+kQBLok9ggemGgMIsZfiJ5jtUISA5Fn4KzWaU+It2qL5Lz42iNRQuPwUTmjxp6ujQLSr2AT2SMmppKov1rbszgXKtapjKZ4NrMEW3ZfQ
X-Received: by 10.52.81.66 with SMTP id y2mr83391vdx.23.1393857562660; Mon, 03 Mar 2014 06:39:22 -0800 (PST)
MIME-Version: 1.0
Received: by 10.52.89.170 with HTTP; Mon, 3 Mar 2014 06:39:02 -0800 (PST)
In-Reply-To: <7594FB04B1934943A5C02806D1A2204B1D1C6595@ESESSMB209.ericsson.se>
References: <7594FB04B1934943A5C02806D1A2204B1D1B55BF@ESESSMB209.ericsson.se> <CAOJ7v-140hQ1JcUkXe9J1U3Ntnz4-LBHC6mLkGj6zHtHVYQKpA@mail.gmail.com> <7594FB04B1934943A5C02806D1A2204B1D1C5BDE@ESESSMB209.ericsson.se> <CAOJ7v-06ZWL9yCGD0UBcosNiDi++eTuAxYH=s-8Z4cPtHegqdw@mail.gmail.com> <7594FB04B1934943A5C02806D1A2204B1D1C63D2@ESESSMB209.ericsson.se> <CAOJ7v-0x+o-5O_D87DgJ8zXN1vhotOHUBsmWJ+OgLX2yVhtTiQ@mail.gmail.com> <7594FB04B1934943A5C02806D1A2204B1D1C6595@ESESSMB209.ericsson.se>
From: Justin Uberti <juberti@google.com>
Date: Mon, 3 Mar 2014 06:39:02 -0800
Message-ID: <CAOJ7v-2vA=TVJXMO2MVj=B14cMswu_HNRW28aQ2fJ_M9LQ3W0A@mail.gmail.com>
To: Christer Holmberg <christer.holmberg@ericsson.com>
Content-Type: multipart/alternative; boundary=001a1136776ae3eb5d04f3b4c02b
Archived-At: http://mailarchive.ietf.org/arch/msg/rtcweb/y3dZFvdtYdPXQ4JqFAWTavMJlWg
Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] JSEP-06: How to create the second offer where only the port numbers are changed?
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.15
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: Mon, 03 Mar 2014 14:39:28 -0000

Agreed.


On Mon, Mar 3, 2014 at 6:35 AM, Christer Holmberg <
christer.holmberg@ericsson.com> wrote:

>  Fair enough, maybe some things can change. And, BUNDLE does not forbid
> changing values, but it does say that the offerer should be careful when
> doing so.
>
>
>
> Section 6.4.3:
>
>
>
> “The Offerer MAY modify any SDP parameter in a BAS Offer.
>
>
>
>    NOTE: It is important that the BAS Offer gets accepted by the
>
>    Answerer, so the Offerer needs to consider the necessity to modify
>
>    SDP parameters that could get the Answerer to reject the BAS Offer.
>
>    Removing "m=" lines, or reducing the number of codecs, in the BAS
>
>    Offer used for the is considered to have a low risk of being
>
>    rejected.”
>
>
>
> So, I guess what should be avoided is adding of new m- lines, new codecs,
> or anything which may trigger the answer to reject the offer.
>
>
>
> Regards,
>
>
>
> Christer
>
>
>
> *From:* Justin Uberti [mailto:juberti@google.com]
> *Sent:* 03 March 2014 16:13
> *To:* Christer Holmberg
> *Cc:* rtcweb@ietf.org
> *Subject:* Re: JSEP-06: How to create the second offer where only the
> port numbers are changed?
>
>
>
> But why is it a problem if other things change (e.g. a=remote-candidates
> is set)?
>
>
>
> On Mon, Mar 3, 2014 at 5:48 AM, Christer Holmberg <
> christer.holmberg@ericsson.com> wrote:
>
>  Hi,
>
>      As specified in BUNDLE, before the remote peer has indicated support
> of BUNDLE, all m- lines (including those within to a bundle group) must
> have unique port numbers.
>
> Then, when the remote peer has indicated support of BUNDLE, a second offer
> (called the BAS offer) needs to be sent, in which the same port number is
> assigned to all m- lines within a bundle group.
>
> My question is: how do I create the BAS offer? I don’t want to change
> anything – I just want to get an SDP with the BUNDLE port assigned to all
> m- lines. Is there a flag in createOffer() for that?
>
>    The implementation knows that any offers that are created after the
> BUNDLE answer should have the same port numbers. So, the app could push the
> createOffer button once it receives the answer if it wanted to ensure this
> happened immediately. Otherwise, there will be an onnegotiationneeded event
> once ICE completes, and the offer sent at that time will have the updated
> ports.
>
> When I call createOffer(), can I be ensure that *only* the port values
> will change?
>
>
>
> No. Why would this be necessary?
>
>
>
> Because the only thing I want to do is to send a new offer, with the same
> port number in each m- line. I don’t want anything else to change.
>
>
>
> Regards,
>
>
>
> Christer
>
>
>