Re: draft-bourbaki-6man-classless-ipv6-00

[Fernando Gont <[e-mail]>]

Hi, Brian,

On 06/13/2017 04:35 AM, Brian E Carpenter wrote:
> On 12/06/2017 13:00, Fernando Gont wrote:
>> On 06/11/2017 09:29 PM, [e-mail] wrote:
[....]
>>>  - Removing the constant from the addressing architecture will likely set these changes into motion.
>>>    (i.e. I don't think a position where one wants to remove the 64 bit constant from 4291 and expect the 64 bit boundary
>>>     to stay in IPv6 over foo is tenable.)
>>
>> Me, I don't think there's a reason to keep the 64 bit constant in
>> ipv6-over-foo documents. Actually, with RFC8064 in place, there's no
>> reason why the IID should be link-type dependent.
> 
> I believe that is simply false unless you want to go back to the era
> of DIP switches with instructions to users to
> a) choose an IID length for their new subnet
> b) set the DIP switches on every device to select that length
> c) then plug and play.
> 
> Otherwise LL addresses cannot be formed consistently on the
> whole link.
> 
> OK, that is caricature, but without a substantial reworking of
> RFC4862 I believe that is essentially what we would need, in
> an automated version, before SLAAC can start.
> 
> Anway, all this is empty talk as long as the addressing architecture
> *requires* 64 bits rather than *recommending* 64 bits.

* Mandate fe80::/64 for link-local
* RECOMMENDED /64 for subnets
* Make SLAAC implementations flexible so that they could do SLAAC if a
non-64 PIO is advertised.

(it's kind of weird that we even have flexibility wrt the prefix length
in parts of 4291, and in the PIO options themselves, and then mandate
one specific value)

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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