Re: [Autoconf] issues with draft-baccelli address model

[sratliff <sratliff at cisco.com>]

On 10/29/09 2:21 PM, "Alexandru Petrescu" <alexandru.petrescu at gmail.com>
wrote:

> Charles E. Perkins a écrit :
> [...]
>> Alexandru Petrescu wrote:
>>> Charles E. Perkins a écrit :
>>> [...]
>>>> So far the only hard problem seems to be how to avoid squabbling over
>>>>  whether link-locals are needed.
>>>> 
>>>> I am not sure why the proponents of necessity are so adept at
>>>> ignoring the solutions that do not need link-locals.
>>> 
>>> It's very simple why: I have a prototype which involves protocol
>>> extensions (RA) only on the parts of the System which use exclusively
>>> link-locals addresses.  You forbidding link-local addresses equates with
>>> forbidding my protocol extensions on the core of my prototype, makes
>>> all break.
>> 
>> I _do not_ forbid link-local addresses.  I'm not even one of the
>> document authors, and I didn't create that language.
>> 
>> But the document does not forbid link-locals either.
> 
> Well it does, here is how:
> 
> draft-baccelli says:
>>   Note that while link-local addresses are assumed to be "on link", the
>>    utility of link-local addresses is limited as described in Section 6.
> 
> The word "limited" strikes.

Nonsense. "utility.. is limited" is not the same as "must not be used".
> 
> draft-baccelli says:
>>    o  A subnet prefix configured on this interface should be of length
>>       /128.
> 
> The link-local prefix of IPv6 LLs is fe80::/10, and not /128.

The key word in that sentence is SHOULD. It does not say MUST.

> 
> draft-baccelli says:
>>    o  Any [IPv4] subnet prefix configured on this interface should be of
>> length
>>       /32.
> 
> Yet the prefix of the IPv4 LL is 169.254/16, and not a /32.
> 

Again, the sentence says SHOULD. Not MUST.


> draft-baccelli says:
>>    Note that the use of IPv4 link-local addresses [RFC3927] in this
>>    context should be discouraged for most applications
> 
> "Discouraged" means discouraged.  And which "context"?  The word
> "context" appears precisely once in the draft.
> 

Precisely. "Discouraged" means discouraged. It doesn't mean "cannot". And
again, the sentence contains the word SHOULD. It does not say MUST.

Regards,
Stan

> These 4 things make me think the draft-baccelli co-authors and Editors
> want to forbid the LLs.
> 
> How do we fix these 4 things such that I don't misunderstand them again?
> 
> Alex
> 
> 
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