IETF Logo Mail Archive

[RAM] Re: The mapping problem: rendezvous points?

David Conrad <drc@virtualized.org> Wed, 09 May 2007 23:24 UTC

Return-path: <ram-bounces@iab.org>
Received: from [127.0.0.1] (helo=stiedprmman1.va.neustar.com) by megatron.ietf.org with esmtp (Exim 4.43) id 1HlvWK-00063u-FD; Wed, 09 May 2007 19:24:32 -0400
Received: from [10.91.34.44] (helo=ietf-mx.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1HlvWJ-00063o-9b for ram@iab.org; Wed, 09 May 2007 19:24:31 -0400
Received: from ns.virtualized.org ([204.152.189.134] helo=mail.virtualized.org) by ietf-mx.ietf.org with esmtp (Exim 4.43) id 1HlvWH-0007he-Ud for ram@iab.org; Wed, 09 May 2007 19:24:31 -0400
Received: from [127.0.0.1] (ns.virtualized.org [204.152.189.134]) by mail.virtualized.org (8.12.9p1/8.12.9) with ESMTP id l49N8OHT070782; Wed, 9 May 2007 16:08:26 -0700 (PDT) (envelope-from drc@virtualized.org)
In-Reply-To: <20070509193151.GA30814@sources.org>
References: <8F47F550-6224-4AFF-8359-CBA98D3F2FAB@muada.com> <271CF87FD652F34DBF877CB0CB5D16FC054EA470@WIN-MSG-21.wingroup.windeploy.ntdev.microsoft.com> <9C228355-9425-4C66-A9A7-47498490E3B1@virtualized.org> <20070509193151.GA30814@sources.org>
Mime-Version: 1.0 (Apple Message framework v752.3)
Content-Type: text/plain; charset="US-ASCII"; delsp="yes"; format="flowed"
Message-Id: <07993B9E-1AF7-4B3D-8DCF-673BC5D06827@virtualized.org>
Content-Transfer-Encoding: 7bit
From: David Conrad <drc@virtualized.org>
Date: Wed, 09 May 2007 16:24:10 -0700
To: Stephane Bortzmeyer <bortzmeyer@nic.fr>
X-Mailer: Apple Mail (2.752.3)
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 93238566e09e6e262849b4f805833007
Cc: ram@iab.org
Subject: [RAM] Re: The mapping problem: rendezvous points?
X-BeenThere: ram@iab.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Routing and Addressing Mailing List <ram.iab.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/ram>, <mailto:ram-request@iab.org?subject=unsubscribe>
List-Archive: <http://www1.ietf.org/pipermail/ram>
List-Post: <mailto:ram@iab.org>
List-Help: <mailto:ram-request@iab.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/ram>, <mailto:ram-request@iab.org?subject=subscribe>
Errors-To: ram-bounces@iab.org

On May 9, 2007, at 12:31 PM, Stephane Bortzmeyer wrote:
>> What applications are adversely affected by a delay in transmitting
>> the first packet?
> The DNS? The first packet is often the last of a transaction.

A good example.  The DNS is unusual for a lot of reasons.  That's why  
having the ITR also be the caching resolver is a good idea.

> A lack of reply because of mapping delay may seriously confuse, for  
> instance,
> BIND's best name server selection.

If you never go back to the name server, what does it matter if BIND  
is confused?  If you do go back, BIND will get revised RTT estimates.

(However, looking at the code in BIND9 (specifically, lib/dns/ 
resolver.c), I believe the resolver will try every 1/2 second the  
first two times before going into exponential backoff, arbitrarily  
setting the initial RTT to 200 ms in the event an RTT is not  
collected on the first attempt.)

Rgds,
-drc


_______________________________________________
RAM mailing list
RAM@iab.org
https://www1.ietf.org/mailman/listinfo/ram

v2.23.0 | Report a Bug | By Email