Re: Last Call: <draft-ietf-6man-rfc4291bis-07.txt> (IP Version 6 Addressing Architecture) to Internet Standard

[Alexandre Petrescu <[e-mail]>]

Le 21/02/2017 à 18:27, Job Snijders a écrit :
> On Tue, Feb 21, 2017 at 09:49:32AM +0900, Lorenzo Colitti wrote:
>> On Tue, Feb 21, 2017 at 8:57 AM, Job Snijders <[e-mail]>; wrote:
>>> ps. The "Write a draft" argument is weak at best, since we are
>>> already are discussing a draft (called
>>> 'draft-ietf-6man-rfc4291bis-07.txt'), which is in IETF Last
>>> call, which means it is in a place to discuss the contents of
>>> that draft. No reason to kick the can down the road.
>>
>> I'm sorry, but that's really how it is. The text you dislike has
>> been the standard for almost 20 years, and is it inappropriate to
>> change it in the context of reclassifying this document from draft
>>  standard to Internet standard.
>
> Or, perhaps it is inappropiate for the -bis document to target
> "Internet Standard" classification at this moment? ¯\_(ツ)_/¯
>
> Especially when solidifying recommendations in an architecture
> Internet Standard-to-be, the utmost care should be taken to verify
> whether the paper reality (RFCs) and operational reality (what people
> do, for $reasons) are aligned.
>
> In those years sufficient data has been collected to conclude that
> /64 is not the "be all and end all". The current paragraph does not
> account for staticly configured environments in which SLAAC plays no
>  role.
>
> Perhaps the following suggestion bridges the gap.
>
> -------
>
> OLD: IPv6 unicast routing is based on prefixes of any valid length up
> to 128 [BCP198].  For example, [RFC6164] standardises 127 bit
> prefixes on inter-router point-to-point links.  However, the
> Interface ID of all unicast addresses, except those that start with
> the binary value 000, is required to be 64 bits long.  The rationale
>  for the 64 bit boundary in IPv6 addresses can be found in [RFC7421]
>
> NEW: IPv6 unicast routing is based on prefixes of any valid length up
> to 128 [BCP198]. When using [SLAAC], [ILNP], or [NPT66] the Interface
> ID of unicast addresses is required to be 64 bits long. In other use
> cases different prefix sizes may be required. For example [RFC6164]
> standardises 127 bit prefixes on inter-router point-to-point links.
> For most use cases, prefix lengths of 64 bits is RECOMMENDED, unless
> there are operational reasons not to do so.

I agree with the NEW paragraph if Ethernet is mentioned, and if its last
paragraph gets updates.

I propose this:
NEW NEW:
> IPv6 unicast routing is based on prefixes of any valid length up to
> 128 [BCP198]. When using [SLAAC]/[Ethernet], [ILNP], or [NPT66] the
> Interface ID of unicast addresses is required to be 64 bits long. In
>  other use cases different prefix sizes may be required. For example
>  [RFC6164] standardises 127 bit prefixes on inter-router
> point-to-point links.  Prefix lengths of 64 bits were observed on
> popular connections and are taught on IPv6 lectures.  Prefix lengths
> of 96 bits were observed at Virtual Machine providers.

[note SLAAC alone can work with /65 too]


> OLD: As noted in Section 2.4, all unicast addresses, except those
> that with the binary value 000, Interface IDs are required to be 64
> bits long.
>
> NEW: *delete, its superfluous*

I agree.  But I dont know whether registries have not set this 000 apart
for maybe 200 years later or so. (it may sound not serious, but I know
there are serious public plans for such long term on other matters).

Alex

>
> -------
>
> Kind regards,
>
> Job
>
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