On Tue, Feb 21, 2017 at 09:49:32AM +0900, Lorenzo Colitti wrote:
> On Tue, Feb 21, 2017 at 8:57 AM, Job Snijders <job@xxxxxxx> 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.
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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.
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*
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Kind regards,
Job