Re: Objection to draft-ietf-6man-rfc4291bis-07.txt

Fernando Gont <fgont@si6networks.com> Thu, 02 March 2017 08:32 UTC

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Subject: Re: Objection to draft-ietf-6man-rfc4291bis-07.txt
To: Iván Arce <iarce@fundacionsadosky.org.ar>, 6man WG <ipv6@ietf.org>
References: <20170223134026.GI5069@gir.theapt.org> <9277BC0B-04F3-4FC1-901E-F83A8F0E02D7@google.com> <58AF6429.70809@foobar.org> <902276E9-0521-4D4E-A42B-C45E64763896@google.com> <58AF726A.3040302@foobar.org> <F7C230DE-4759-4B78-ABF2-6799F85B3C62@google.com> <58B014F6.2040400@foobar.org> <6DA95097-8730-4353-A0C9-3EB4719EA891@google.com> <CAKD1Yr0qk_njAGnex_FZsYisCVw=eM8hXTr1v+wqvcfX_09wiQ@mail.gmail.com> <CAN-Dau0ohz3Wp55bs+eoFvSyoUjuKfjzKGSAsJS3wUt3z7TGtA@mail.gmail.com> <CAKD1Yr0wK8EiAbz39EZz-xZLtsSV2JROSzNECKtGo36Zc=RZ0Q@mail.gmail.com> <CAN-Dau2N-fv3o9o4807m_fbMktjC6hq28sMZhfECKg5cbb4g6Q@mail.gmail.com> <CAKD1Yr3tHm5x29w4L5KtKi7PqDHRxkPr6i9mJMtHLaPc2eM2GQ@mail.gmail.com> <8ce32e32-3f71-81fc-6bf5-763a4d85fed0@fundacionsadosky.org.ar> <0a3446a1-c7d2-a914-25c1-2c4cf11041b7@gmail.com> <b6432ced-1fe5-7d29-4084-37f7446d29f0@fundacionsadosky.org.ar>
From: Fernando Gont <fgont@si6networks.com>
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On 03/01/2017 08:07 PM, Iván Arce wrote:
[....]
> 
> Either not mentioning /64 at all or just saying it is recommended but
> leaving the specifics to a "IPv6 over X" specification is better than
> bolting a fixed prefix len in the standard.
> 
> Incidentally, I think this should have been deprecated in RFC 7136 when
> EUI-64 was (sortof) killed.

Modified EUI-64 should have been killed a long time ago. But Lorenzo has
been very loud in keeping that flawed approach alive.

For instance, RFC8064 recommends against its use for stable addresses,
but leaves the door open for employing Modified EUI-64 if the underlying
link-layer address has been randomized -- a scheme that is still flawed
because, among other things, it unnecessarily wastes 18 bits of entropy
and follows a well-known bad practice of re-using numeric IDs across
different layers and contexts.

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492