IETF Logo Mail Archive

Re: [rtcweb] Tunnelling DTLS in SDP

Harald Alvestrand <harald@alvestrand.no> Mon, 04 April 2016 20:42 UTC

Return-Path: <harald@alvestrand.no>
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 C302812D895 for <rtcweb@ietfa.amsl.com>; Mon, 4 Apr 2016 13:42:17 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.909
X-Spam-Level:
X-Spam-Status: No, score=-1.909 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, T_RP_MATCHES_RCVD=-0.01] 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 OVOXHpPva17R for <rtcweb@ietfa.amsl.com>; Mon, 4 Apr 2016 13:42:14 -0700 (PDT)
Received: from mork.alvestrand.no (mork.alvestrand.no [IPv6:2001:700:1:2::117]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 5284912D815 for <rtcweb@ietf.org>; Mon, 4 Apr 2016 13:42:14 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by mork.alvestrand.no (Postfix) with ESMTP id BD3397C7BD2 for <rtcweb@ietf.org>; Mon, 4 Apr 2016 22:42:12 +0200 (CEST)
X-Virus-Scanned: Debian amavisd-new at alvestrand.no
Received: from mork.alvestrand.no ([127.0.0.1]) by localhost (mork.alvestrand.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AQZq2p2mwgAA for <rtcweb@ietf.org>; Mon, 4 Apr 2016 22:42:11 +0200 (CEST)
Received: from [IPv6:2001:67c:370:136:2154:8066:f6ed:c7f7] (unknown [IPv6:2001:67c:370:136:2154:8066:f6ed:c7f7]) by mork.alvestrand.no (Postfix) with ESMTPSA id 2CBDB7C7BC2 for <rtcweb@ietf.org>; Mon, 4 Apr 2016 22:42:10 +0200 (CEST)
To: rtcweb@ietf.org
References: <CABcZeBOM1KoXpXFhvjS753EVpsMENWVen3CCdFj8ry36vPH0dg@mail.gmail.com> <D5416C24-0032-48CB-8CC6-FD5D4E046C0D@phonefromhere.com>
From: Harald Alvestrand <harald@alvestrand.no>
Message-ID: <5702D19F.9030305@alvestrand.no>
Date: Mon, 04 Apr 2016 22:42:07 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <D5416C24-0032-48CB-8CC6-FD5D4E046C0D@phonefromhere.com>
Content-Type: multipart/alternative; boundary="------------040307010908010001010300"
Archived-At: <http://mailarchive.ietf.org/arch/msg/rtcweb/_YjHAo7U4-GyQEDIls0NC8eVeC4>
Subject: Re: [rtcweb] Tunnelling DTLS in SDP
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/rtcweb/>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 04 Apr 2016 20:42:18 -0000

On 04/04/2016 05:39 PM, pfh wrote:
>
>> On 4 Apr 2016, at 14:10, Eric Rescorla <ekr@rtfm.com
>> <mailto:ekr@rtfm.com>> wrote:
>>
>> Hi folks,
>>
>> I wanted to call your attention to a draft I just published with a
>> possibly stupid
>> idea.
>>
>> https://tools.ietf.org/html/draft-rescorla-dtls-in-sdp-00
>>
>> A nontrivial fraction of call setup time in WebRTC is the DTLS handshake.
>> This document describes how to piggyback the first few handshake messages
>> in the SDP offer/answer exchange, thus reducing latency.
>
> It strikes me we could get the same reduced latency benefits by
> piggybacking on ICE
> rather than SDP, e.g. embedding the DTLS packet as data in a new STUN
> attribute type.

Piggybacking in ICE means that you have to repeat it in every probe
packet, since you don't know which is going to make it through.

And you can't start ICE probing until the handshake has completed.

v2.23.0 | Report a Bug | By Email