Re: [MMUSIC] Mirja Kühlewind's Discuss on draft-ietf-mmusic-sctp-sdp-23: (with DISCUSS)

Christer Holmberg <christer.holmberg@ericsson.com> Thu, 16 February 2017 15:16 UTC

Return-Path: <christer.holmberg@ericsson.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 52A5612962F; Thu, 16 Feb 2017 07:16:23 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.221
X-Spam-Level:
X-Spam-Status: No, score=-4.221 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_PASS=-0.001] autolearn=ham autolearn_force=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 Rs_Cy8VrdlbT; Thu, 16 Feb 2017 07:16:21 -0800 (PST)
Received: from sessmg23.ericsson.net (sessmg23.ericsson.net [193.180.251.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 105D012943F; Thu, 16 Feb 2017 07:16:20 -0800 (PST)
X-AuditID: c1b4fb2d-18e0e98000005112-f9-58a5c243e8eb
Received: from ESESSHC008.ericsson.se (Unknown_Domain [153.88.183.42]) by (Symantec Mail Security) with SMTP id 6C.DE.20754.342C5A85; Thu, 16 Feb 2017 16:16:19 +0100 (CET)
Received: from ESESSMB209.ericsson.se ([169.254.9.76]) by ESESSHC008.ericsson.se ([153.88.183.42]) with mapi id 14.03.0319.002; Thu, 16 Feb 2017 16:14:57 +0100
From: Christer Holmberg <christer.holmberg@ericsson.com>
To: "Mirja Kuehlewind (IETF)" <ietf@kuehlewind.net>, Eric Rescorla <ekr@rtfm.com>
Thread-Topic: =?utf-8?B?TWlyamEgS8O8aGxld2luZCdzIERpc2N1c3Mgb24gZHJhZnQtaWV0Zi1tbXVz?= =?utf-8?Q?ic-sctp-sdp-23:_(with_DISCUSS)?=
Thread-Index: AQHSiEaxS+qNKsn/A0y+WNY+OfKww6Frs1fQ///1IwCAABFeUP//8EEAgAAA4YCAABIiwA==
Date: Thu, 16 Feb 2017 15:14:56 +0000
Message-ID: <7594FB04B1934943A5C02806D1A2204B4C0043DA@ESESSMB209.ericsson.se>
References: <148724403323.15929.1432579178871938006.idtracker@ietfa.amsl.com> <7594FB04B1934943A5C02806D1A2204B4C0040D6@ESESSMB209.ericsson.se> <9F29D433-0AE1-43B0-B13E-AEC2861DFE75@kuehlewind.net> <7594FB04B1934943A5C02806D1A2204B4C00438C@ESESSMB209.ericsson.se> <CABcZeBPPFUe-ZtW9Lt636OhoMH8ws2oVi94YQJeUQKXteC-XRg@mail.gmail.com> <81A8D5E0-6641-4136-AFE6-74D3C49C7707@kuehlewind.net>
In-Reply-To: <81A8D5E0-6641-4136-AFE6-74D3C49C7707@kuehlewind.net>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [153.88.183.154]
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrAIsWRmVeSWpSXmKPExsUyM2K7lq7zoaURBrP7RSxerZvPbLHi9Tl2 i/cXdC1m/JnIbPHi+kdmi/M71zNZTF3+mMWB3WPK742sHkuW/GTyaPm4kNVj8uM25gCWKC6b lNSczLLUIn27BK6MXc9OsxUcEag42HyJsYGxR6CLkZNDQsBE4tbPBqYuRi4OIYF1jBIre3ZD OYsZJX5OvsnaxcjBwSZgIdH9TxukQUQgWOLc05vMIDXMAp8YJf693csK4ggLNDFKrFvcAuaI CDQzSpze8IAFoiVMom3/HnYQm0VAVeLbopOMIDavgK/ElvaZLBDrepglHnftZgNJcAo4SVw8 d4UVxGYUEJP4fmoNE4jNLCAucevJfCaIwwUkluw5zwxhi0q8fPyPFcJWklh0+zMTyNnMApoS 63fpQ7QqSkzpfsgOsVdQ4uTMJywTGEVnIZk6C6FjFpKOWUg6FjCyrGIULU4tLs5NNzLWSy3K TC4uzs/Ty0st2cQIjLeDW37r7mBc/drxEKMAB6MSD2/BvqURQqyJZcWVuYcYJTiYlUR4M9YC hXhTEiurUovy44tKc1KLDzFKc7AoifOarbwfLiSQnliSmp2aWpBaBJNl4uCUamDsbvbP/6fb +MRx+Vxllr+n2K5rdB1pUp/FNWv/PPUHOvvzJ/DUzVvJKhY9le9m00Hzq9L+G27IbIq2uTxN 9b+WacrNowa18vySBr/vT/285ceOZ1Zz03d+mnRw+6KFx5xXHzXSEvt/z3J/dbm7twvrLZkM votVzqdk8q9mttzfd16DUbcgnHOHEktxRqKhFnNRcSIAYDxCqLMCAAA=
Archived-At: <https://mailarchive.ietf.org/arch/msg/mmusic/2vucj80PB-GBe9MpGdjmsGYAq1E>
Cc: "fandreas@cisco.com" <fandreas@cisco.com>, "mmusic-chairs@ietf.org" <mmusic-chairs@ietf.org>, "draft-ietf-mmusic-sctp-sdp@ietf.org" <draft-ietf-mmusic-sctp-sdp@ietf.org>, "mmusic@ietf.org" <mmusic@ietf.org>, The IESG <iesg@ietf.org>
Subject: Re: [MMUSIC] =?utf-8?q?Mirja_K=C3=BChlewind=27s_Discuss_on_draft-ietf?= =?utf-8?q?-mmusic-sctp-sdp-23=3A_=28with_DISCUSS=29?=
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, 16 Feb 2017 15:16:23 -0000

Hi,

>By making the transport stack overly complicated? That really gives me headache…
>
>But let me get back the the other question you asked: Is the TCP variant really needed here? Is this implemented or are there any plans to implement that?

I'd have to double check whether e.g., the WebRTC data channel mandates support of TCP, but in any case draft-sctp-sdp recommends to only use it when UDP does not work.

Regards,

Christer




> Am 16.02.2017 um 16:02 schrieb Eric Rescorla <ekr@rtfm.com>om>:
> 
> As Christer says. This design is optimized for making the media stack 
> simpler, which using TLS here would not do.
> 
> -Ekr
> 
> 
> 
> 
> On Thu, Feb 16, 2017 at 7:00 AM, Christer Holmberg <christer.holmberg@ericsson.com> wrote:
> Hi,
> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> >>> Why is this using TCP/DTLS/SCTP instead of TCP/TLS/SCTP?
> >>>
> >> Because the way it is realized is by transporting SCTP on top of 
> >> DTLS (as defined in draft-ietf-tsvwg-sctp-dtls-encaps) and transporting DTLS on top of TCP (defined in RFC 4571).
> >
> > I got this but DTLS is a mapping to use TLS with UDP because UDP is 
> > an unreliable datagram transport. If you use TCP, you should use TLS. And rfc4571 is not a mapping of DTLS to TCP.
> 
> The framing mechanism of RFC 4571 is used, with DTLS packets sent instead of RTP packets.
> 
> Regards,
> 
> Christer
> 
>