Re: [tram] Points that should be clarified in STUN-bis and TURN-bis

Paul Kyzivat <pkyzivat@alum.mit.edu> Mon, 10 February 2014 16:54 UTC

Return-Path: <pkyzivat@alum.mit.edu>
X-Original-To: tram@ietfa.amsl.com
Delivered-To: tram@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 397271A06E4 for <tram@ietfa.amsl.com>; Mon, 10 Feb 2014 08:54:44 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.235
X-Spam-Level:
X-Spam-Status: No, score=-1.235 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, SPF_SOFTFAIL=0.665] 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 RHEFZFBkM91G for <tram@ietfa.amsl.com>; Mon, 10 Feb 2014 08:54:42 -0800 (PST)
Received: from qmta09.westchester.pa.mail.comcast.net (qmta09.westchester.pa.mail.comcast.net [IPv6:2001:558:fe14:43:76:96:62:96]) by ietfa.amsl.com (Postfix) with ESMTP id ADF3A1A06DC for <tram@ietf.org>; Mon, 10 Feb 2014 08:54:42 -0800 (PST)
Received: from omta03.westchester.pa.mail.comcast.net ([76.96.62.27]) by qmta09.westchester.pa.mail.comcast.net with comcast id QdK81n0040bG4ec59guiBZ; Mon, 10 Feb 2014 16:54:42 +0000
Received: from Paul-Kyzivats-MacBook-Pro.local ([50.138.229.164]) by omta03.westchester.pa.mail.comcast.net with comcast id Qgui1n00D3ZTu2S3PguisY; Mon, 10 Feb 2014 16:54:42 +0000
Message-ID: <52F90452.3090401@alum.mit.edu>
Date: Mon, 10 Feb 2014 11:54:42 -0500
From: Paul Kyzivat <pkyzivat@alum.mit.edu>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:24.0) Gecko/20100101 Thunderbird/24.3.0
MIME-Version: 1.0
To: tram@ietf.org
References: <16037E0F-62BC-484C-87C0-0C4190ED4D66@vidyo.com> <52F53C98.1070202@viagenie.ca> <CALDtMr+qgdnT5i4fiJidufGZF1CPR=puAZ+Ldqnp5t=At0AS-g@mail.gmail.com> <52F54CDC.1040502@viagenie.ca> <CALDtMrJ4J78t4PboxN5O3ZPMmt243zZ2YV5LBv-Nhz1k3E7LyQ@mail.gmail.com> <52F5550D.3020203@viagenie.ca> <CALDtMrLdxC8Vdge-XQuU0kmF1YaiRQXGZm=6mExbA6LwsnNGow@mail.gmail.com> <52F7C7E7.7050005@alum.mit.edu> <CALDtMrJvH4r3yLTMcXR9PiC-bQVSf3RSS-OoVmxY9s=8RnpQJQ@mail.gmail.com> <52F83D0F.2090301@alum.mit.edu> <52F8E1E4.3030406@viagenie.ca> <52F8EDC4.8040101@alum.mit.edu> <52F90039.9040901@viagenie.ca>
In-Reply-To: <52F90039.9040901@viagenie.ca>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 8bit
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1392051282; bh=ZInw5qqeMClKKuYQHcn5j8ei2CMkYgNEejhE18ZSs50=; h=Received:Received:Message-ID:Date:From:MIME-Version:To:Subject: Content-Type; b=V/TZyKs5HXGiX4+rNiMYeLt71cPpdmwiDrkLLAlJGNsh/mQV5pTBb/nd3uC+EgZdl 7g/WrI5MlOfZOUwODqj3qkgDqLqqV+LO/JxCipthNwc3bAxMRoWS2LEAi3CXXM/2PO AWiTr2W4PD0SMiByiilBe2H9135/cnvsVnImcObU+Bk7ZW2HYLsHtukJhl5r4+KNBg O75+6eYo4+2W0A2QE5Pv9zgfwWbRoeeyM7KZoDraq6jnpPKhrmhY3L6yIquMj9ldeV zksrL+gST1L/sN1TEsFGz1ERAg2Pt7hJxr64dv+VRjZL6Gnjsq585/PMzda0YbCCYp cyYaQFRuSQWww==
Subject: Re: [tram] Points that should be clarified in STUN-bis and TURN-bis
X-BeenThere: tram@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: "Discussing the creation of a Turn Revised And Modernized \(TRAM\) WG, which goal is to consolidate the various initiatives to update TURN and STUN." <tram.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tram>, <mailto:tram-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/tram/>
List-Post: <mailto:tram@ietf.org>
List-Help: <mailto:tram-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tram>, <mailto:tram-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 10 Feb 2014 16:54:44 -0000

On 2/10/14 11:37 AM, Simon Perreault wrote:
> Le 2014-02-10 10:18, Paul Kyzivat a écrit :
>>> Option 3 means you don't have to keep backward compatibility around
>>> forever. Practically, all TURN-bis servers would be backward compatible
>>> from day 1. Then as time passes the client population would gradually
>>> migrate to TURN-bis. When the non-TURN-bis client population becomes too
>>> small to justify the cost of backward compatibility, you can throw
>>> compat away. For example, if you start a new implementation of STUN
>>> today, it could be possible to ignore STUNv1 (depending on your target
>>> market), and thus make the implementation smaller, simpler, easier to
>>> test, and faster to develop.
>>
>> It would be more of an issue of there was a real issue if there was a
>> significant cost to supporting backward compatibility. But IIRC, the
>> only cost for backward compatibility here is filling in a standard
>> default if the parameter is missing.
>
> You are correct in this particular instance, of course. In general,
> things may be different.

My philosophy is to start out assuming backward compatibility.
If something is found that makes that much of a burden, then discuss 
what to do about it.

>> The consequence of not requiring backward compatibility is that a
>> developer does exactly as you describe above - ignore STUNv1
>> compatibility in his server because he thinks his target market won't
>> need it. Then it turns out that there is a STUNv1 client. And that
>> client just fails because of this.
>
> Correct. And then either 1) the developer realizes that this STUNv1
> client is important enough to warrant additional development, or 2) the
> developer says "tough luck" to the client, and the client's only
> recourse it to upgrade to STUNv2. IMHO, that's exactly the kind of
> thinking that we want to encourage! :)

If the new thing isn't compatible with TURNv1 then call it something 
different, so that the process of discovering a TURN server only gets 
the appropriate kind.

> Anyway, we're just philosophizing, this has no practical impact on
> anything at this point.

Sure.

	Thanks,
	Paul