Re: [DNSOP] Enough latency obsession Re: Review of draft-ietf-dnsop-cookies-00
Mukund Sivaraman <muks@isc.org> Wed, 17 December 2014 00:51 UTC
Return-Path: <muks@isc.org>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8B0B71A1A1D for <dnsop@ietfa.amsl.com>; Tue, 16 Dec 2014 16:51:28 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.235
X-Spam-Level:
X-Spam-Status: No, score=-1.235 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_SOFTFAIL=0.665] autolearn=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 Vt_7WVG6mHcn for <dnsop@ietfa.amsl.com>; Tue, 16 Dec 2014 16:51:27 -0800 (PST)
Received: from mail.banu.com (mail.banu.com [46.4.129.225]) by ietfa.amsl.com (Postfix) with ESMTP id 626E01A1A1B for <dnsop@ietf.org>; Tue, 16 Dec 2014 16:51:27 -0800 (PST)
Received: from totoro.home.mukund.org (unknown [115.118.144.63]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.banu.com (Postfix) with ESMTPSA id 7DA9CE60035; Wed, 17 Dec 2014 00:51:23 +0000 (GMT)
Date: Wed, 17 Dec 2014 06:21:17 +0530
From: Mukund Sivaraman <muks@isc.org>
To: Nicholas Weaver <nweaver@icsi.berkeley.edu>
Message-ID: <20141217005117.GA27187@totoro.home.mukund.org>
References: <20141216152511.GA22255@totoro.home.mukund.org> <20141216171318.GA23468@totoro.home.mukund.org> <549069CC.20309@redbarn.org> <EE59F273-8E3F-4F0E-A3AA-B8256DE5B3BD@icsi.berkeley.edu>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="UugvWAfsgieZRqgk"
Content-Disposition: inline
In-Reply-To: <EE59F273-8E3F-4F0E-A3AA-B8256DE5B3BD@icsi.berkeley.edu>
User-Agent: Mutt/1.5.23 (2014-03-12)
Archived-At: http://mailarchive.ietf.org/arch/msg/dnsop/3MRN1dQyHnIXdiAbABD6U-wB0O0
Cc: dnsop@ietf.org, Paul Vixie <paul@redbarn.org>
Subject: Re: [DNSOP] Enough latency obsession Re: Review of draft-ietf-dnsop-cookies-00
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: IETF DNSOP WG mailing list <dnsop.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dnsop>, <mailto:dnsop-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/dnsop/>
List-Post: <mailto:dnsop@ietf.org>
List-Help: <mailto:dnsop-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dnsop>, <mailto:dnsop-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 17 Dec 2014 00:51:28 -0000
Hi Nicholas On Tue, Dec 16, 2014 at 02:44:40PM -0500, Nicholas Weaver wrote: > > Its time to stop obsessing over latency in DNS! > > DNS doesn't exist in a vacuum, but then goes to at minimum, a TCP > handshake, and who knows what else beyond it. Amdahl's law matters. > > How many headaches would go away if all DNS is over TCP? And how much > would it really make a difference in Latency? Surely a lot of problems would go away. But I don't think we can say that latency doesn't matter. Though it is 2 roundtrips instead of 1, the wait effectively doubles, and may increase further by a ~constant factor during recursion. This would be conspicuous on long networks. As DNS resolution is at the head of the batch of items that is done when a user uses a network service, it adds to the average turnaround time of every item on the list. TCP performance "feels" different depending on what it is used for. On LFNs, slow-start can throttle up fast (being a doubling throttle), and due to the receive window TCP can deliver a lot of data quickly vs. DNS-like UDP that restricts flow to request/response pairs. For DNS, where there isn't a lot of data to transmit (in normal queries), TCP connection setup is a big part of overall time to service a request and it may not amortize well. Mukund
- [DNSOP] Review of draft-ietf-dnsop-cookies-00 Mukund Sivaraman
- Re: [DNSOP] Review of draft-ietf-dnsop-cookies-00 Mukund Sivaraman
- Re: [DNSOP] Review of draft-ietf-dnsop-cookies-00 Paul Vixie
- Re: [DNSOP] Review of draft-ietf-dnsop-cookies-00 Mukund Sivaraman
- Re: [DNSOP] Review of draft-ietf-dnsop-cookies-00 P Vixie
- [DNSOP] Enough latency obsession Re: Review of dr… Nicholas Weaver
- [DNSOP] Enough latency obsession Re: Review of dr… Nicholas Weaver
- Re: [DNSOP] Enough latency obsession Re: Review o… Mukund Sivaraman
- Re: [DNSOP] Review of draft-ietf-dnsop-cookies-00 Mukund Sivaraman
- Re: [DNSOP] Enough latency obsession Re: Review o… Stephane Bortzmeyer
- Re: [DNSOP] Enough latency obsession Re: Review o… Guangqing Deng
- Re: [DNSOP] Enough latency obsession Re: Review o… Paul Vixie