IETF Logo Mail Archive

Re: [RAM] Re: Tunneling overheads and fragmentation

Iljitsch van Beijnum <iljitsch@muada.com> Thu, 19 July 2007 16:25 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 1IBYp8-0008AW-Ok; Thu, 19 Jul 2007 12:25:54 -0400
Received: from [10.91.34.44] (helo=ietf-mx.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1IBYp7-0008AB-St for ram@iab.org; Thu, 19 Jul 2007 12:25:53 -0400
Received: from sequoia.muada.com ([83.149.65.1]) by ietf-mx.ietf.org with esmtp (Exim 4.43) id 1IBYp5-00035Q-SV for ram@iab.org; Thu, 19 Jul 2007 12:25:53 -0400
Received: from [82.192.90.28] (nirrti.muada.com [82.192.90.28]) (authenticated bits=0) by sequoia.muada.com (8.13.3/8.13.3) with ESMTP id l6JGMbuI053729 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Thu, 19 Jul 2007 18:22:41 +0200 (CEST) (envelope-from iljitsch@muada.com)
In-Reply-To: <20070719160125.GA16217@nic.fr>
References: <469F7673.6070702@firstpr.com.au> <20070719160125.GA16217@nic.fr>
Mime-Version: 1.0 (Apple Message framework v752.3)
Content-Type: text/plain; charset="US-ASCII"; delsp="yes"; format="flowed"
Message-Id: <C360C6BC-5562-4118-B1A4-934743397B74@muada.com>
Content-Transfer-Encoding: 7bit
From: Iljitsch van Beijnum <iljitsch@muada.com>
Subject: Re: [RAM] Re: Tunneling overheads and fragmentation
Date: Thu, 19 Jul 2007 18:24:28 +0200
To: Stephane Bortzmeyer <bortzmeyer@nic.fr>
X-Mailer: Apple Mail (2.752.3)
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 79899194edc4f33a41f49410777972f8
Cc: Robin Whittle <rw@firstpr.com.au>, ram@iab.org
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 19-jul-2007, at 18:01, Stephane Bortzmeyer wrote:

>> For instance, if all provider and transit routers happily handle
>> packets significantly longer than whatever hosts normally produce
>> (say 1500 bytes) then adding the encapsulation won't lead to any
>> fragmentation.  Is this a reasonable assumption?

> I do not think so.

Agree, if you assume this, you'll get bitten.

However, I think it's a reasonable _requirement_. Hosts are connected  
by ethernet or PPP with an MTU of 1500 (or smaller) in nearly all  
cases, but it's just ethernet that lives in the 1970s with its 1500  
byte MTU but very little gigabit ethernet equipment sold this century  
can't do jumboframes to some degree.

It would also help to raise the internet MTU in general, of course:

http://www.ietf.org/internet-drafts/draft-van-beijnum-multi-mtu-00.txt

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

v2.23.0 | Report a Bug | By Email