[dhcwg] draft-ietf-dhc-dna-ipv4 Issue 40: DHCP Client Identifier

On Wed, Nov 23, 2005 at 08:30:57AM -0800, Bernard Aboba wrote:
> Issue 40: DHCP Client Identifier
> Submitter name: David Hankins
> Submitter email address: david_hankins@isc.org
> Date first submitted: November 11, 2005
> Document: DNA-17
> Comment type: T
> Priority: S
> Section: 1.1
> Rationale/Explanation of issue: 

... snip ...

> I can take a stab at it if you'd prefer to keep the example.

In the meantime, Mr. Aboba has updated the draft to level 18, removing
the example and adding the client-id to the list of explicit things
a client implementing dna should remember about a candidate
configuration.

This is great, but it solves the problem of the pink elephant in our
living room by simply choosing not to talk about it.

So, I would like to suggest that section 2.1 receive a fourth
condition for a DNAv4 client to skip candidate configurations;

    [d] The contents of the DHCP Client Identifier option the client
	used to obtain the candidate configuration is, even slightly,
	different from the Client Identifier option the client intends
	to present on the interface now being addressed, or a comparison
	is impossible because either or both sources do not use Client
	Identifier options.  In these cases, it is anticipated that a
	DHCP server would NAK any request made by the client to acquire
	or extend the candidate configuration, since the two interfaces
	are presenting differing identities.

I think this is the neatest and lowest impact way to both suggest to the
implementor "hey, look at other interfaces maybe!" and give them precisely
the logic they need to avoid DHCP server NAKs later on in operating if
they do.

In hindsight now, it's possible the example removed in the 17->18 edits
could be reintroduced along with the above statement, but I still think
the example is provocative without being encumbered by so many words to
describe the failure modes as to crush it.

Perhaps with an explicit nod to the section 2.1 qualifications.

-- 
David W. Hankins		"If you don't do it right the first time,
Software Engineer			you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins