Re: [sunset4] review of sunset4-gap-analysis

[Simon Perreault <[e-mail]>]

Le 2012-11-12 17:47, Lee Howard a écrit :
> I promised to review the document.  I have not included proofreading notes
> (spelling, grammar, etc.) but I would be happy to do so.

Thanks! Sorry for taking so long to reply. Busy...

> Abstract:
> "and identifies the gaps resulting in additional work"
> /resulting in/requiring

Ok.

> Related work: the RFCs in this list are lists of RFCs requiring IPv4.  Have
> the authors reviewed them to see whether any protocol work is required?  The
> documents often point to works-in-progress as of 2004; has all of that work
> been completed?

As Wes said.

I just don't want to go there. It was a tremendous amount of work when 
that review was being done. But it had a different goal: identifying 
IPv4-only stuff in protocols. Our goal is different because we're 
focusing on the operational side: what prevents people from actually 
turning off IPv4. Sometimes it can be related to IPv4-only protocol 
elements, but often not. A protocol having an IPv4-only element doesn't 
mean IPv4 can't be turned off.

> PROBLEM 1.  I could argue that failure to find a DHCP server is a failure
> condition.  It may not be a fatal error, but more specificity is needed
> here.  What happens that's bad?
> How do you tell the difference between "The DHCP (IPv4) server is down" and
> "IPv4 is gone forever"?

Exactly. There's no way to tell. And because there's no way to tell, it 
creates the problems listed here:
<http://tools.ietf.org/html/draft-perreault-sunset4-noipv4-01#section-3>

> PROBLEM 2.  Which DHCP messages do you mean?  Do you mean in Advertise
> messages?

DHCPOFFER

> Does a server send an Offer if it has no addresses?

The problem is not that it has no address. For example, a home router 
always has an RFC1918 address on its LAN interface. The problem is that 
it sends an offer even when it has no IPv4 access on its WAN interface.

> What about
> when there's no IPv4 on the WAN, but IPv4 is still needed for internal
> communication?

No need for DHCP. Just use link-local IPv4 addresses. [RFC3927]

> PROBLEM 3.  Separate problem descriptions are needed for home networks and
> enterprise networks.

First, we're not saying all problems apply to all networks.

Second, I'm not sure separating the draft in a home section and an 
enterprise section would be useful: some problems would apply to both, 
and some problems would apply to none (home+enterprise != internet).

> This document either needs to include a section on "How to know you IPv4
> isn't needed any more" or needs to say explicitly, "The decision about when
> to turn off IPv4 is out of scope."

As Wes said.

Text proposal:

>       <t>The decision about when to turn off IPv4 is out of scope. This document
>         merely attempts to enumerate the issues one might encounter if that
>         decision is made.</t>

Thanks,
Simon
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