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Re: Gen-ART LC/Telechat Review of draft-ietf-isis-genapp-03.txt

2010-10-06 15:04:12

On Oct 6, 2010, at 10:14 AM, Les Ginsberg (ginsberg) wrote:


[...]


From RFC 5226:

"Specification Required - Values and their meanings must be
          documented in a permanent and readily available public
          specification, in sufficient detail so that
interoperability
          between independent implementations is possible.  When
used,
          Specification Required also implies use of a Designated
          Expert, who will review the public specification..."

We deliberately chose "Specification Required" because:

a)It requires a public specification
b)It allows the public specification to be other than an RFC
c)It requires expert review

Completing the sentence in your quote: "who will review the public
specification and evaluate whether it is sufficiently clear to allow
interoperable implementations."

My understanding of "Specification Required" is that the expert review
is merely to ensure that the documentation is sufficiently complete
and
readable to implement in an interoperable way. That review is not
intended to ensure compliance to other criteria specified in the
draft.

However, the draft includes some specific criteria for GENINFO
applications. If you want the reviewer to enforce those criteria, then
I think you need at least "Expert Review". OTOH, in RFC5226, the
"expert review" policy has less to say about the required level of
documentation, so the draft might require some more meat in that area.


This is a bit distressing - because you are suggesting that RFC 5226
doesn't define a category which is appropriate for our usage - which
means we have to try to define a unique policy. I am not quite sure how
to do that with sufficient authority and minimal controversy.

My understanding is that RFC 5226 is specific to IANA considerations -
so we have attempted to define a clear policy as to how the review of
code point assignments is done.

Beyond that, it seems clear that a given Application specification could
specify behavior that might be seen as undesirable e.g. it could specify
some extremely high rate of updates. Given that we allow application
specification to be defined in public documents from a variety of
sources, I don't see how we could define an enforceable review policy
for the application specifications. It is at the IANA codepoint
allocation that we have control - and certainly it seems within the
purview of an expert to say "I think your specification is flawed and I
won't approve the allocation of codepoints until the issues of concern
are addressed".



Yes, both "specification required" and "expert review" involve expert review. 
But they have significant differences in the scope of the review. 
"Specification required" means that the expert should review to make sure the 
specification is clear enough to be implemented in an interoperable fashion. It 
doesn't in any way indicate that the expert thinks the code point is "good", or 
that it conforms to the purpose of the registry. Certainly, the expert could 
offer advise on issues, but the registrant would not be under any obligation to 
follow the advise.

"Expert Review" means that the expert should review a registration to make sure 
that it conforms to the criteria set forth in the document that defined the 
registry. I really think that is what you are looking for, particularly from 
your last sentence above about the expert being able to block allocation of a 
flawed code point.

For example, RFC 3563 calls out "Expert Review", and sets a number of criteria, 
one of which is the assertion that registrations require standards actions, or 
that they require publications from  ISO/IEC JTC1/SC6 that meant the normal 
requirements for an RFC.

In your case, I think you need Expert Review, with criteria along the lines 
that registrants must meet the requirements of "specification required", that 
it must describe its expected rate of updates (and that this not be excessive), 
that it must address any security considerations, etc.


I note that while RFC3563, which established the IS-IS TLV Codepoint
registry, says "Expert Review", the review criteria is pretty much
equivalent to "standards action". I'm guessing the only reason it was
not "standards action" was to allow ISO/IEC JTC1/SC6 to submit
specifications, which are to be held to the same standard as a
standards-track RFC, but do not actually get published as such. So for
practical purposes, the proposed policy for GENINFO is significantly
weaker than for the parent registry--more so than one might think from
just looking at the registry itself.

I am not clear on why "Expert Review" is seen as a stronger review
criteria than "Specification Required" - which includes expert review as
well as a requirement for a public specification.

Actually, "expert review" doesn't have to be stronger than specification 
required. But it can be. It's all a matter of how you define the review 
criteria. The difference is, in "expert review" you get to define the criteria. 
In "specification required", the criteria is already defined, and fairly 
limited.

RFC3563 has has quite strict criteria, thus my comment about it being 
"stronger". For all practical purposes, the policy for RFC 3563 is "standards 
action" with some very specific exceptions.

[...]


If the revised version of a GENINFO TLV is sent in an LSP with a
different number from the previous version there can be transient
windows where other systems have two copies of information regarding
the
same application. This may be unavoidable. For completeness we
specify
that the choice of what to do in such transient situations is
implementation specific (undefined). This section does specify ways
to
minimize the occurrence/duration of such transient periods.

Does leaving this undefined cause interop issues? If not, then no
problem.

There is no alternative. It is not possible to determine in a reliable
way which copy is "newer".

Okay

[...]



Since the registration policy is not at least "RFC Required", there's
no explicit requirement that the public document actually do this. If
you wish to require them to do it, you will need to state something to
that effect. (See previous comment about whether the registration
policy actually enforces that sort of criteria.)

I appreciate your point - but I don't see how we have the authority to
place a requirement on a document developed in another standards body.


You can set criteria for the codepoint allocation, though. Requiring the 
specification of a code point to address security seems to be a reasonable 
criteria.
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