Re: Fwd: New Version Notification for draft-hinden-ipv4flag-00.txt

[Brian E Carpenter <[e-mail]>]

On 17/11/2017 20:57, Fernando Gont wrote:
> HI, BOb,
> 
> Comments/questions:
> 
> * How about the case in which a user employs an IPv4-only printer on an
> IPv6-only network?

That question makes my head hurt. Why would you configure the flag =1 on
such a network?

> 
> * Does this document imply that IPv6 is bootstrapped first than, or in
> parallel of, IPv4?

First. Maybe we need to state that.

> 
> * If IPv4-has already been bootstrapped, would 4=1 still cause the node
> to disable IPv4?

There is a cunning "should not" in the text to cover corner cases. But
we probably need to discuss the corner cases anyway.

> 
> * If 4=1, but later 4=0, shuld that transition of the 4 bit trigger IPv4
> configuration?

Yes, we need to say something about that - linked to router lifetimes, I
think.

me -> airport shortly.

   Brian
> 
> 
> * Sec cons: see RFC7113 -- it seems that still the current state of
> affairs for many implementations (unfortunately).
> 
> 
> Thanks!
> 
> Cheers,
> Fernando
> 
> 
> 
> 
> On 11/17/2017 02:42 PM, Bob Hinden wrote:
>> Hi,
>>
>> Brian and I took a cut a defining an IPv4 Availability Flag for IPv6 ND
>> Router Advertisements.  From the Introduction:
>>
>>    Hosts that support IPv4 and IPv6, usually called dual stack hosts,
>>    need to work on IPv6 only networks.  That is, a link where there are
>>    no IPv4 routers and/or IPv4 services.  Monitoring of IPv6-only
>>    networks, for example at the IETF 100 meeting in Singapore, shows
>>    that current dual stack hosts will create local auto-configured IPv4
>>    addresses and attempt to reach IPv4 services.  A mechanism is needed
>>    to inform hosts that there is no IPv4 support and that they should
>>    turn off IPv4.
>>
>>    Because there is no IPv4 support on these links, the only way to
>>    notify the dual stack hosts on the link is to use an IPv6 mechanism.
>>    An active notification will be much more robust than attempting to
>>    deduce this state by the lack of IPv4 responses or traffic.
>>
>>    IPv4-only hosts, and dual-stack hosts that do not recognize the new
>>    flag, will continue to attempt IPv4 operations, in particular IPv4
>>    discovery protocols typically sent as link-layer broadcasts.  This
>>    legacy traffic cannot be prevented by any IPv6 mechanism.  The value
>>    of the new flag is limited to dual-stack hosts that recognize it.
>>
>> We were originally thinking it would be an April 1 submission, but after
>> reading the discussion on the IPv6 list, we decided it makes sense as a
>> real submission :-)
>>
>> Please review and comment.
>>
>> Thanks,
>> Bob and Brian
>>
>>
>>> Begin forwarded message:
>>>
>>> *From: *[e-mail] <mailto:[e-mail]>
>>> *Subject: **New Version Notification for draft-hinden-ipv4flag-00.txt*
>>> *Date: *November 17, 2017 at 2:36:31 PM GMT+8
>>> *To: *"Robert M. Hinden" <[e-mail]
>>> <mailto:[e-mail]>>, "Robert Hinden" <[e-mail]
>>> <mailto:[e-mail]>>, "Brian Carpenter"
>>> <[e-mail] <mailto:[e-mail]>>
>>>
>>>
>>> A new version of I-D, draft-hinden-ipv4flag-00.txt
>>> has been successfully submitted by Robert M. Hinden and posted to the
>>> IETF repository.
>>>
>>> Name:draft-hinden-ipv4flag
>>> Revision:00
>>> Title:IPv6 Router Advertisement IPv4 Availability Flag
>>> Document date:2017-11-17
>>> Group:Individual Submission
>>> Pages:5
>>> URL:
>>>            https://www.ietf.org/internet-drafts/draft-hinden-ipv4flag-00.txt
>>> Status:         https://datatracker.ietf.org/doc/draft-hinden-ipv4flag/
>>> Htmlized:       https://tools.ietf.org/html/draft-hinden-ipv4flag-00
>>> Htmlized:
>>>       https://datatracker.ietf.org/doc/html/draft-hinden-ipv4flag-00
>>>
>>>
>>> Abstract:
>>>   This document specifies a Router Advertisement Flag to indicate that
>>>   there is no IPv4 service on the advertising router.  This document
>>>   updates RFC5175.
>>>
>>>
>>>
>>>
>>> Please note that it may take a couple of minutes from the time of
>>> submission
>>> until the htmlized version and diff are available at tools.ietf.org
>>> <http://tools.ietf.org>.
>>>
>>> The IETF Secretariat
>>>
>>
>>
>>
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> 
>