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Re: Non-Last Small IPv6 Fragments

Mikael Abrahamsson <swmike@swm.pp.se> Fri, 11 January 2019 07:24 UTC

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Date: Fri, 11 Jan 2019 08:24:42 +0100
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Mark Andrews <marka@isc.org>
cc: Tom Herbert <tom@herbertland.com>, IPv6 List <ipv6@ietf.org>, "ek@loon.co" <ek@loon.co>, Bob Hinden <bob.hinden@gmail.com>
Subject: Re: Non-Last Small IPv6 Fragments
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On Fri, 11 Jan 2019, Mark Andrews wrote:

> A resonable limit is 1280/2.  This allow a 1281 packet to be split into 
> 2 even sizes packets.  Even sized packets have less reordering issues 
> than all PMTU but the last.

I have seen implementations in the wild that do just this, fragments a 
packet into two evenly sized packets.

So while I am sympathetic to disallowing very small non-last fragments, I 
think requiring all non-last fragments to be 1280 is too strict. 1280/2 or 
something similar to that sounds like a reasonable tradeoff.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se

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