Re: IPv6 PTMU query

Mark Smith <ipng@69706e6720323030352d30312d31340a.nosense.org> Thu, 26 April 2007 11:24 UTC

Return-path: <ipv6-bounces@ietf.org>
Received: from [127.0.0.1] (helo=stiedprmman1.va.neustar.com) by megatron.ietf.org with esmtp (Exim 4.43) id 1Hh25Q-0000kW-Bg; Thu, 26 Apr 2007 07:24:32 -0400
Received: from [10.91.34.44] (helo=ietf-mx.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1Hh25O-0000kJ-Ba for ipv6@ietf.org; Thu, 26 Apr 2007 07:24:30 -0400
Received: from mistral.mail.adnap.net.au ([203.6.132.90]) by ietf-mx.ietf.org with esmtp (Exim 4.43) id 1Hh25M-0006in-TQ for ipv6@ietf.org; Thu, 26 Apr 2007 07:24:30 -0400
Received: from 219-90-233-111.ip.adam.com.au ([219.90.233.111] helo=mail.nosense.org) by mistral.mail.adnap.net.au with esmtp (Exim 4.60 (FreeBSD)) (envelope-from <ipng@69706e6720323030352d30312d31340a.nosense.org>) id 1Hh25J-000E5X-3z; Thu, 26 Apr 2007 20:54:25 +0930
Received: from ubu.nosense.org (localhost.localdomain [127.0.0.1]) by mail.nosense.org (Postfix) with SMTP id A8DD71FF53; Thu, 26 Apr 2007 20:54:23 +0930 (CST)
Date: Thu, 26 Apr 2007 20:54:23 +0930
From: Mark Smith <ipng@69706e6720323030352d30312d31340a.nosense.org>
To: vijaykumar@huawei.com
Message-Id: <20070426205423.a1441499.ipng@69706e6720323030352d30312d31340a.nosense.org>
In-Reply-To: <000901c78669$6778b340$6005120a@china.huawei.com>
References: <000901c78669$6778b340$6005120a@china.huawei.com>
X-Mailer: Sylpheed 2.4.0 (GTK+ 2.10.11; i686-pc-linux-gnu)
X-Location: Lower Mitcham, South Australia, 5062
Mime-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
X-Spam-Score: 0.1 (/)
X-Scan-Signature: bb8f917bb6b8da28fc948aeffb74aa17
Cc: ipv6@ietf.org
Subject: Re: IPv6 PTMU query
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "IP Version 6 Working Group \(ipv6\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
Errors-To: ipv6-bounces@ietf.org

Hi Vijay,

On Tue, 24 Apr 2007 17:39:26 +0530
vijay <vijaykumar@huawei.com> wrote:

> Hi All,
> 
>  
> 
>        I am currently analyzing the IPv6 path MTU.
> 
> As the IPv6 path MTU calculation is done by error correction method, I was
> thinking of suggesting a
> 
> proposal for calculating the path MTU optimally. I am interested in knowing
> if the path MTU is a problem 
> 
> in real networks and how often packets are dropped due to MTU too small, in
> real networks? 
> 
>  
> 
>        If there is some information regarding the same, please share it.
> 

Just in case you aren't aware of it, a recent RFC specifies a mechanism
to use probing of Path MTUs via different sizes of packets rather than
ICMP error feedback :

"RFC4821 - Packetization Layer Path MTU Discovery"

There is also an implementation of this in fairly recent Linux kernels.

HTH,
Mark.

--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6@ietf.org
Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------