Re: [MMUSIC] JSEP Issue #394: What appears in m= lines.
Eric Rescorla <ekr@rtfm.com> Thu, 22 December 2016 17:31 UTC
Return-Path: <ekr@rtfm.com>
X-Original-To: mmusic@ietfa.amsl.com
Delivered-To: mmusic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A157E1296F7 for <mmusic@ietfa.amsl.com>; Thu, 22 Dec 2016 09:31:31 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=rtfm-com.20150623.gappssmtp.com
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 zgWvAYfBvHuM for <mmusic@ietfa.amsl.com>; Thu, 22 Dec 2016 09:31:30 -0800 (PST)
Received: from mail-yw0-x229.google.com (mail-yw0-x229.google.com [IPv6:2607:f8b0:4002:c05::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id BD4ED129695 for <mmusic@ietf.org>; Thu, 22 Dec 2016 09:31:29 -0800 (PST)
Received: by mail-yw0-x229.google.com with SMTP id a10so118513217ywa.3 for <mmusic@ietf.org>; Thu, 22 Dec 2016 09:31:29 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rtfm-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=q1FLDKS8Dvc9T1BKKvT8eB44QXVl/yhBQl3C2+yWHh4=; b=Vdgf0nGLdQB6riI1uHICu+c+7cvvyrp2MrSWDg+d5c3UqzAE7MaEqHulqIwujOWTuh S4ABeV7opEwwjDLxRGkXfLis5GDt5xv8V/OQ9K2VwlmjWI8OdEjl0BOZFfCZVuFewCrr thLZsMz84Vj5dblCr2uQH7VsmUFIe0y21HVKZD0+ezBq6tb3A84o80IXMC8jzNOrBqpM yMhW/XmqnagFgkPYpXPWrwTB93bfumjcCq2xZndD0saNbdATR9DIt6q9NTIscGrYnNSK pBDnkgseC7Pj5Zw/T4o6y8OlgNjYePBN83s+ljb1LWnQ9qcvWEXzwCAS7JcR+0O/69sU iiyA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=q1FLDKS8Dvc9T1BKKvT8eB44QXVl/yhBQl3C2+yWHh4=; b=gqU6qa4ktQMxE7oUNKe12ful+sE3daNBXLJx3v6RLKVlmERj+meZWkAV8Tm/8pbJpS YGL6C7jl98B6+iPBV+lNVpzKmDrUzWUKiBLc0JI/OgmKjlp2Jh8SUEEVxstXYCCHvtqT MEe46+2Ax8mL9VRm3Bl+zcxUZU4ZLkbwnx7WXCwPE71xJW872sBjjzDEeitVZivOgSR6 qpa2Vre+T3qplawq9PiFKFUyIDBMkNS+5L+iXvX6J7znAknxgg+Rr/idKX4lMzSlKJTS JL50UgdJhN/1v7VG/Rs5yTZdHtWi2WZ5a1kxmqm9YlPT4QCDIGLbmN5ItazpMTeqvIUR wYXQ==
X-Gm-Message-State: AIkVDXJt732yZ2S0tRhTwUwkq69R421XuKGXRXb6GH+0bAp8DpIL8jWxQYqIKzpA7ckdkwkLcJ8QLUTte8dfnw==
X-Received: by 10.129.125.215 with SMTP id y206mr8499840ywc.234.1482427888970; Thu, 22 Dec 2016 09:31:28 -0800 (PST)
MIME-Version: 1.0
Received: by 10.129.164.210 with HTTP; Thu, 22 Dec 2016 09:30:48 -0800 (PST)
In-Reply-To: <52E4A8FC978E0241AE652516E24CAF001E483F95@ESESSMB309.ericsson.se>
References: <52E4A8FC978E0241AE652516E24CAF001E483F95@ESESSMB309.ericsson.se>
From: Eric Rescorla <ekr@rtfm.com>
Date: Thu, 22 Dec 2016 09:30:48 -0800
Message-ID: <CABcZeBPznLKNHek-SGE5Ly6QTOBL-j65sZBb5MbwQVkmBkpyFw@mail.gmail.com>
To: Magnus Westerlund <magnus.westerlund@ericsson.com>
Content-Type: multipart/alternative; boundary="001a11492dfaba7b15054442a35a"
Archived-At: <https://mailarchive.ietf.org/arch/msg/mmusic/LJ4u5tr57-qxxZ3v5yvLlYSxJdw>
Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>, mmusic WG <mmusic@ietf.org>
Subject: Re: [MMUSIC] JSEP Issue #394: What appears in m= lines.
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Multiparty Multimedia Session Control Working Group <mmusic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mmusic>, <mailto:mmusic-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/mmusic/>
List-Post: <mailto:mmusic@ietf.org>
List-Help: <mailto:mmusic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mmusic>, <mailto:mmusic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 22 Dec 2016 17:31:31 -0000
On Thu, Dec 22, 2016 at 7:15 AM, Magnus Westerlund < magnus.westerlund@ericsson.com> wrote: > Hi, > > > > See inline. > > > > Den 2016-12-16 kl. 18:05, skrev Eric Rescorla: > > > https://github.com/rtcweb-wg/jsep/issues/394 > > > > > > Magnus writes: > > > > > > > For media m= sections, JSEP endpoints MUST support both the > > > "UDP/TLS/ > > > > RTP/SAVPF" and "TCP/DTLS/RTP/SAVPF" profiles and MUST indicate > > > one of > > > > these two profiles for each media m= line they produce in an > > > offer. > > > > > > > > > > > > Do I understand this correct, we are requiring support for the > > > "TCP/DTLS/RTP/SAVPF" proto so that in cases an endpoint supports the > > > optional to support ICE TCP, they can indicate it, and any WebRTC > > > endpoint will accept it, even if that is just one option? I do know > > > that different profiles are a negotiation issue. But, wouldn't it be > > > more reasonable in this case to use UDP/TLS/RTP/SAVPF in all cases > > > where one offer any candidates that also use UDP? And only use > > > TCP/DTLS/RTP/SAVPF in cases only TCP candidates are signalled, thus > > > not forcing TCP/DTLS/RTP/SAVPF onto clients that doesn't support it?" > > > > > > > > > We could certainly do this, but it seems to perpetuate the idea that the > > > TCP/UDP distinction is > > > > > > meaningful here, which seems like the opposite direction from the one we > > > are going in (see > > > > > > the mmusic minutes around the topic Non-Supported Transport in m- line). > > > See also the note below in this paragraph about either profile being > > > consistent with either transport. > > > > > > > > > I think it would be fine to relax the requirement that implementations > > > *support* both UDP and TCP, but requiring them to conditionally use one > > > or the other depending on whether they have UDP candidates seems like > > > it's really going to impose a lot of pain on implementors for no good > > > reason, in part because you don't necessarily know at the time of offer > > > generation what you will have. Consider the case where you are only > > > offering relayed and srflx candidates. At the time of generation, you > > > don't know if you will be able to get a UDP candidate, because you might > > > be behind a firewall that blocks UDP and your TURN server might be down. > > > > > > > Okay, I agree that having any rules for what you should offer here based > on what the actual outcome is not the best idea here. I think the rules > should be based on capability and intent. So if you only are going offer > TCP candidates, then you clearly should use TCP/…, > I'm going to push on this. If we've already agreed that mismatches are normal, why should we do that? Wouldn't it be better to just effectively deprecate this field? -Ekr If you have no implementation for TCP candidates then you clearly offers > UDP/…. If the implementations intention is to offer both if they are > determined, then one has a choice. In the context of WebRTC to WebRTC this > does would not matter, as long as the counter part has the rule to accept > either. However if you support both, if one you uses UDP, then it also > doesn’t matter for implementations supporting only UDP, they will accept > it. If the incoming offer is TCP/… then with the clarifications you propose > below a non TCP candidate supporting implementations answering can’t fail > immediately. It will have to wait to see if there if there ever shows up > any UDP candidates. > > > > Gateways to legacy devices will independently have issues, as what they > need to use will depend on the far sides capabilities and the actual set of > candidates. > > > > > > > > If we make any change, I think it should just be to relax the > > > requirement to support TCP and then tell people to ignore the first > > > field here in favor of the candidate lines. > > > > > > > So, if I interpret the above, I would say: Set the PROTO to UDP/… and on > reception ignore the TCP/UDP part of the PROTO string, only looking at > candidates. That is very close to my amended suggestion. The only addition > I have, is that if an implementation will not include any UDP candidates, > only TCP one, then it shall use TCP. > > > > > > We should have defined ICE/DTLS/RTP/SAVPF to avoid this issue. > > > > > > Cheers > > > > Magnus Westerlund > > > > ---------------------------------------------------------------------- > > Services, Media and Network features, Ericsson Research EAB/TXM > > ---------------------------------------------------------------------- > > Ericsson AB | Phone +46 10 7148287 > <+46%2010%20714%2082%2087> > > Färögatan 6 | Mobile +46 73 0949079 > <+46%2073%20094%2090%2079> > > SE-164 80 Stockholm, Sweden | mailto: magnus.westerlund@ericsson.com > > ---------------------------------------------------------------------- >
- [MMUSIC] JSEP Issue #394: What appears in m= line… Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Magnus Westerlund
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Harald Alvestrand
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Magnus Westerlund
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Magnus Westerlund
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Harald Alvestrand
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Paul Kyzivat
- Re: [MMUSIC] [rtcweb] JSEP Issue #394: What appea… Jonathan Lennox
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Roman Shpount
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Paul Kyzivat
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Roman Shpount
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Paul Kyzivat
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Magnus Westerlund
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Christer Holmberg
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Christer Holmberg
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Roman Shpount
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Roman Shpount
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Roman Shpount
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Eric Rescorla
- Re: [MMUSIC] JSEP Issue #394: What appears in m= … Roman Shpount