Return-Path: 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 0F78F130DE3 for ; Tue, 29 Jan 2019 13:53:26 -0800 (PST) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -2.041 X-Spam-Level: X-Spam-Status: No, score=-2.041 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_MED=-0.142, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001] 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 QEghcw53ixLj for ; Tue, 29 Jan 2019 13:53:24 -0800 (PST) Received: from mail-lj1-x231.google.com (mail-lj1-x231.google.com [IPv6:2a00:1450:4864:20::231]) (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 CA683130DC9 for ; Tue, 29 Jan 2019 13:53:23 -0800 (PST) Received: by mail-lj1-x231.google.com with SMTP id s5-v6so18845870ljd.12 for ; Tue, 29 Jan 2019 13:53:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rtfm-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pQdJKpwH+UEDTSYRZDw7zs+NLGIYi6Lz0IoURVPPXLg=; b=P2DK9/KHo2NFdz7TibeRgKIGr+UGanTGmVGgygzxa2DNy3fQYcOInqvhZJQiXIgG+w uA6erO1YIq21Mfe3lp4VoVgxGakpsKKsxFRlblQCkmVcxOdnSxcm2pySiIhYI7UfcIal RUvxAWK1hn+vskT/5K/5AvSsyFmb0aJgWdp9ppt4eElIvVZR1wWf9//plN3GUItgSqtK T0+TdYuG5ZSZl6KfLcML+ch7aXniT2wr0NKL7+L/PfAKKMxZ5RX0HsbP1EPUqWdv3pbC QvGN/TE5uUL82wLKPkUfw+PhGYKx21Ulhu+0PEPmpXkj/rtJ4ifBfUklKgBCLlJvA5DM tIdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pQdJKpwH+UEDTSYRZDw7zs+NLGIYi6Lz0IoURVPPXLg=; b=AzD0s1aglPnkfgTC6Ltj0GHq11fG4GO4gw7i/nXt4bqYVC4lQPUnn16xlTbzdKh8RP hdChhQgHMuOpFosb7SmAv4rfv8Ys43xTrpk8dk2I2yLzWEmh+5HUdVTR1rA8iqcMG/oB 1BXLVAh/BGmKKcm03L838/x2Hb+sA24LYYZsbwQ1aL5dglNFDFvbatE/iPXqoRd8GSSd 0TxVDj76kAagvdS5J3jmZGDEsOZZt1CO6bo3AT9OE/m9h9j1ULlq7242g6sUNv6s1Cb7 C6GgQpTZchzWzWi0zHaap18QEuerVYGv1CnOIRnsUq/V94D+EwkDc+PM6NuUxfri+3Se DsMg== X-Gm-Message-State: AJcUukdOjULSr1eZESjVCGrlMJpSGP18ozFjcsBosWnN4mOfLM8wQmdj rQgXps7gQdNdE3uRvXp8mTwDa0dNRLyoyDVIOwWF+fsh X-Google-Smtp-Source: ALg8bN5aRP+sqY/Buzp5LBGTEwW2bOo4W6EhwmvyEXPr1X/PLaIcwa9MsXPDYOEZhiNXy77EEhl7hPbLbwoonnmXXik= X-Received: by 2002:a2e:95c6:: with SMTP id y6-v6mr19985769ljh.59.1548798801914; Tue, 29 Jan 2019 13:53:21 -0800 (PST) MIME-Version: 1.0 References: <97ed2641-8a7e-19a9-be38-a3458ca9212e@nostrum.com> <961E55AE-2072-4145-8BCF-62D67C6D150F@mozilla.com> In-Reply-To: From: Eric Rescorla Date: Tue, 29 Jan 2019 13:52:43 -0800 Message-ID: To: Roman Shpount Cc: =?UTF-8?Q?I=C3=B1aki_Baz_Castillo?= , RTCWeb IETF Content-Type: multipart/alternative; boundary="0000000000006ac15f05809fd257" Archived-At: Subject: Re: [rtcweb] Proposal to break the ICE impasse X-BeenThere: rtcweb@ietf.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Real-Time Communication in WEB-browsers working group list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Jan 2019 21:53:26 -0000 --0000000000006ac15f05809fd257 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Jan 29, 2019 at 11:28 AM Roman Shpount wrote: > On Tue, Jan 29, 2019 at 2:05 PM I=C3=B1aki Baz Castillo w= rote: > >> I understand your point. But still I don't understand the purpose of the >> new draft (set TCP/DTLS/etc in proto line if there are just TCP candidat= es >> in the offer). >> > > The purpose is standard compliance. If nominated candidate is UDP, proto > line should be UDP. If nominated candidate is TCP, proto line should be > TCP. If you do not care about the c=3D and m=3D line, put the dummy value= s and > UDP there, but this breaks legacy interop by causing ICE mismatch. > This is two separate statements that don't necessarily follow form each other 1. This is a matter of standards compliance. 2. It breaks legacy interop I agree on point (1). I'm still waiting for someone to demonstrate point (2= ) -Ekr Putting UDP proto and address from TCP candidate breaks legacy interop as > well, but it is typically localized to provider managed server, so it is > possible to patch around this either in JS client or on the server to tre= at > WebRTC clients differently. Alternatively, WebRTC clients can add a coupl= e > lines of code and become compliant with the RFC they decided to implement > and remove the need for patching. > > Of course, if browser follow the ICE spec and set the selected candidate >> in the c/m lines, they must also indicate whether that is over UDP or TC= P. >> The problem here is what such a proto line is intended to mean when ther= e >> is ICE candidates of UDP and TCP. But ok, let's assume that browser do >> update c/m lines in the trigger with the selected candidate, and they JU= ST >> change the proto line to TCP/DTLS if there are just TCP candidates. Now >> thing about this scenario: >> >> 1) Client initial offer with UDP and TCP candidates. >> >> 2) Server answers with both UDP and TCP candidates. >> >> 3.1) UDP is selected. Re-offer is created with just UDP candidates (as >> per spec). >> >> 3.2) or TCP is selected. Re-offer is created with just TCP candidates (a= s >> per specs). >> >> In both 3.1 and 3.2 the "monitoring Node" doesn't need to inspect the >> proto line. It can just check the protocol (UDP or TCP) of *any* candida= te >> in the offer to know whether UDP or TCP was selected. >> >> Am I wrong? >> > > You are correct. Checking c=3D and m=3D line is simply to avoid checking = and > parsing ICE candidates. If monitoring client would handle ICE candidates, > then the monitoring client would still need to figure out which candidate > is default to record client media IP. Keeping c=3D and m=3D line in sync = with > default candidate on the client seemed to cause the least amount of > problems which is why it was left in ice-sip-sdp. > > Regards, > _____________ > Roman Shpount > > _______________________________________________ > rtcweb mailing list > rtcweb@ietf.org > https://www.ietf.org/mailman/listinfo/rtcweb > --0000000000006ac15f05809fd257 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Tue, Jan 29, 2019 at 11:28 AM Roma= n Shpount <roman@telurix.com>= ; wrote:
On Tue, Jan 29, 2019 at 2:05 PM I=C3=B1aki Baz C= astillo <ibc@aliax.ne= t> wrote:
I understand your= point. But still I don't understand the purpose of the new draft (set = TCP/DTLS/etc in proto line if there are just TCP candidates in the offer).<= /div>
=C2=A0
The purpose is standard compliance.= If nominated candidate is UDP, proto line should be UDP. If nominated cand= idate is TCP, proto line should be TCP. If you do not care about the c=3D a= nd m=3D line, put the dummy values and UDP there, but this breaks legacy in= terop by causing ICE mismatch.

This is two separate statements that don't necessarily follow for= m each other

1. This is a matter of standards comp= liance.
2. It breaks legacy interop

I ag= ree on point (1). I'm still waiting for someone to demonstrate point (2= )

-Ekr

Putting UDP proto and address from TCP candidate breaks legacy interop as= well, but it is typically localized to provider managed server, so it is p= ossible to patch around this either in JS client or on the server to treat = WebRTC clients differently. Alternatively, WebRTC clients can add a couple = lines of code and become compliant with the RFC they decided to implement a= nd remove the need for patching.

Of course, = if browser follow the ICE spec and set the selected candidate in the c/m li= nes, they must also indicate whether that is over UDP or TCP. The problem h= ere is what such a proto line is intended to mean when there is ICE candida= tes of UDP and TCP. But ok, let's assume that browser do update c/m lin= es in the trigger with the selected candidate, and they JUST change the pro= to line to TCP/DTLS if there are just TCP candidates. Now thing about this = scenario:

1) Client = initial offer with UDP and TCP candidates.

2) Server answers with both UDP and TCP candidates.

3.1) UDP is selected. Re-off= er is created with just UDP candidates (as per spec).

3.2) or TCP is selected. Re-offer is created = with just TCP candidates (as per specs).

<= div dir=3D"auto">In both 3.1 and 3.2 the "monitoring Node" doesn&= #39;t need to inspect the proto line. It can just check the protocol (UDP o= r TCP) of *any* candidate in the offer to know whether UDP or TCP was selec= ted.

Am I wrong?

You are correct. Checking c=3D and m= =3D line is simply to avoid checking and parsing ICE candidates. If monitor= ing client would handle ICE candidates, then the monitoring client would st= ill need to figure out which candidate is default to record client media IP= . Keeping c=3D and m=3D line in sync with default candidate on the client s= eemed to cause the least amount of problems which is why it was left in ice= -sip-sdp.

Regards,
_____________
Roman Shp= ount
=C2=A0
_______________________________________________
rtcweb mailing list
rtcweb@ietf.org https://www.ietf.org/mailman/listinfo/rtcweb
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