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Re: Is Fragmentation at IP layer even needed ?

Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp> Fri, 12 February 2016 04:49 UTC

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Subject: Re: Is Fragmentation at IP layer even needed ?
To: Mark Andrews <marka@isc.org>
References: <CAOJ6w=EvzE3dM4Y2mFFR=9YyPBdmFu_jkF4-42LjkdbRd3yz_w@mail.gmail.com> <20160208200943.A615941B5B96@rock.dv.isc.org> <CAMm+LwgLoYpQ1TNOTOuJzh+cu+GyRBf9=y_K7K35boQ9WcZKjA@mail.gmail.com> <56B92A96.9050200@si6networks.com> <CAMm+LwifTXvVd1mPZOfcOOR03Fnj-82H9aDVS01=wGezePtnXw@mail.gmail.com> <56BA4BC7.1010002@isi.edu> <CAMm+Lwi-n=be4AWGibs+Zq9egYw5pSDmPGb-4P0LDEcX1E6osA@mail.gmail.com> <56BA68CE.7090304@isi.edu> <CAMm+LwiM2sFUeejgJZe650UQbVHrh7EHrEF2omvPrZJPodgJLA@mail.gmail.com> <56BA739D.7060309@isi.edu> <CAMm+Lwij1dOkK0b2ZnJiPMtba=wc823WgYjqw0iwAApa3KBYcg@mail.gmail.com> <56BA95C7.8060109@isi.edu> <56BAD6CC.2030209@necom830.hpcl.titech.ac.jp> <56BBAAF7.6020903@isi.edu> <56BC9516.6050305@necom830.hpcl.titech.ac.jp> <56BCCBB4.4050909@isi.edu> <56BCF514.6040401@necom830.hpcl.titech.ac.jp> <20160212033031.39F25420758B@rock.dv.isc.org> <56BD58DF.9020508@necom830.hpcl.titech.ac.jp> <20160212043208.7DA5B420839B@rock.dv.isc.org>
From: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>
Message-ID: <56BD644B.8020302@necom830.hpcl.titech.ac.jp>
Date: Fri, 12 Feb 2016 13:49:15 +0900
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Mark Andrews wrote:

>> It is caused primarily by stupid design of IPv6.

> Given you see the same stupidity of devices dropping IPv4 fragments

Stupidity is in IPv6 having fragments even with minimum MTU of
1280B and lengthy extension headers to make transport header
obscure, neither of which has anything to do with IPv4. And,
wrong fix of rfc7112 has made the situation worse.

OTOH, IPv4 fragmentation is there because it was necessary for
possible network environment at the time it was designed.

						Masataka Ohta

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