[MMUSIC] DTLS-SRTP client/server role negotiation

Gustavo García <ggb@tokbox.com> Wed, 01 May 2013 18:27 UTC

Return-Path: <ggb@tokbox.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 726AE21F94E1 for <mmusic@ietfa.amsl.com>; Wed, 1 May 2013 11:27:02 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.299
X-Spam-Level:
X-Spam-Status: No, score=-6.299 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, MIME_8BIT_HEADER=0.3, RCVD_IN_DNSWL_MED=-4]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rsCqV6tpYZz4 for <mmusic@ietfa.amsl.com>; Wed, 1 May 2013 11:26:56 -0700 (PDT)
Received: from na3sys010aog113.obsmtp.com (na3sys010aog113.obsmtp.com [74.125.245.94]) by ietfa.amsl.com (Postfix) with SMTP id 04BEA21F9684 for <mmusic@ietf.org>; Wed, 1 May 2013 11:26:55 -0700 (PDT)
Received: from mail-pa0-f69.google.com ([209.85.220.69]) (using TLSv1) by na3sys010aob113.postini.com ([74.125.244.12]) with SMTP ID DSNKUYFeb+h2JMSCXa9+e3Zv0m14JnjJewod@postini.com; Wed, 01 May 2013 11:26:56 PDT
Received: by mail-pa0-f69.google.com with SMTP id kl13so1794354pab.0 for <mmusic@ietf.org>; Wed, 01 May 2013 11:26:55 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-received:x-received:from:content-type:content-transfer-encoding :subject:date:message-id:to:mime-version:x-mailer:x-gm-message-state; bh=uvuMbPYklyzlFSmlCven0I+YYZeEcaVlVvJawEFGSeM=; b=o0lngGbDMepddOLDD1RNaRDMfiKUq32za1yoEHX42XGoaShvQqh8ZF5P4C/jDLOvBO JR0xj44TQUIl+A9BsaEqLmgm944sLRXfaKwxu7SdDoWPLaEEXcRC0vtTi4Aw6KF8wXtL 7tIz22wfssEHF7P3rCB0lk2dSrG+2Glkso1VutIi3ZLOcTFnFTsSb4Au3tBAff/7Qt50 1yPPj4900u79qWCrazidojxA0MLqERWhqGABgRJjXMTHIVajw2cGWPMeCLEEsLbLoJrS /+1Z3hyNYPzZ+rFTtp6PkY2BsykoBJQTJ2mKg2a8lo4IpVnUWlkDnMxubSkO0xV/ZJtn oVCA==
X-Received: by 10.68.26.6 with SMTP id h6mr5321534pbg.149.1367432814951; Wed, 01 May 2013 11:26:54 -0700 (PDT)
X-Received: by 10.68.26.6 with SMTP id h6mr5321524pbg.149.1367432814737; Wed, 01 May 2013 11:26:54 -0700 (PDT)
Received: from [192.168.10.114] (ginger.tokbox.com. [216.38.134.117]) by mx.google.com with ESMTPSA id aj6sm3897974pbd.14.2013.05.01.11.26.53 for <mmusic@ietf.org> (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 01 May 2013 11:26:53 -0700 (PDT)
From: Gustavo García <ggb@tokbox.com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Date: Wed, 01 May 2013 11:26:52 -0700
Message-Id: <E888F149-12FE-4F23-A270-F861123BAC7B@tokbox.com>
To: mmusic@ietf.org
Mime-Version: 1.0 (Apple Message framework v1283)
X-Mailer: Apple Mail (2.1283)
X-Gm-Message-State: ALoCoQnUT5ci6Bn/tCBmXmp3u9b01n4o/I5rJacZtasMDx5Nr8hKG2fywqCISUiLIh3+M/k7vUmRGxqFi/NdO0Va9aV4P7E7uaVDUNA+9Nl0gDXOvke62V19tyUKhABTtwD6mxRvuXc0cjgyShfeh/aYlu6y4+t1pg==
Subject: [MMUSIC] DTLS-SRTP client/server role negotiation
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.12
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: <http://www.ietf.org/mail-archive/web/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: Wed, 01 May 2013 18:27:02 -0000

RFC5764 (DTLS-SRTP) states that "Which side is the DTLS client and which side is the DTLS server must be established via some out-of-band mechanism such as SDP."

What is the specification on how to signal that in SDP?  

Specifically in case of 3pcc where both endpoints are SDP offerers which one should take the client and server roles for DTLS?    Should we tie that role to ICE controlled/controlling roles or should we negotiate it in the SDP somehow?

G.