[65664] in North American Network Operators' Group
Re: MTU path discovery and IPSec
daemon@ATHENA.MIT.EDU (Joe Maimon)
Thu Dec 4 16:43:56 2003
Date: Thu, 04 Dec 2003 16:40:45 -0500
From: Joe Maimon <jmaimon@ttec.com>
To: nanog@merit.edu
In-Reply-To: <OF2E6E897F.BC61BD22-ON88256DF2.00740F5A-88256DF2.00758EBE@us.ibm.com>
Errors-To: owner-nanog-outgoing@merit.edu
Tony Rall wrote:
>On Wednesday, 2003-12-03 at 09:38 PST, David Sinn <dsinn@dsinn.com> wrote:
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<snipped>
>(And note that frag 1 often is not the first fragment to arrive at
>downstream nodes. In my example in (1), frequently frag 2 will reach
>places before frag 1 does (if any router along the path reorders its
>transmit queue based on packet size).)
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I agree with all I have snipped.
I was wondering would it not be wiser for fraggers to frag in half
instead of just the overflow?
For instance, suppose router has to fragment 1500 byte packet to go over
1476 GRE. Instead of having a big packet/little fragment why not just
divide in half?
This would give them more equal buffer treatment, but an even bigger
potential win is to avoid perhaps a second (maybe ipsec?) fragmenting
later on down the pipe.
Once you are going to do it, do it right. It is not as if your
decreasing header overhead by producing small fragment packets. And I am
assuming the whole packet is already in buffer when it comes time to
fragment it.
>Tony Rall
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