Re: Objection to draft-ietf-6man-rfc4291bis-07.txt

[Iván Arce <[e-mail]>]

El 1/3/17 a las 16:48, Brian E Carpenter escribió:
> On 02/03/2017 06:03, Iván Arce wrote:
>> El 1/3/17 a las 6:51, Lorenzo Colitti escribió:
>>
>>>
>>>         Another thing I think we should avoid is to remove the fixed 64
>>>         barrier and open the door to having this debate again and again,
>>>         once for every new IPv6-over-foo document and once for every new
>>>         address configuration protocol (today we have SLAAC and DHCPv6,
>>>         who knows what we'll have in the future).
>>>
>>>
>>>     Which is why it time to get this right and saying it is now and
>>>     forever 64 isn't right.
>>>
>>>
>>> Do you agree that a fixed boundary is useful or not? For 20 years the
>>> standards have guaranteed that 64 bits of IIDs were available to hosts
>>> that wanted to use them. If we make that barrier mobile, there will be
>>> no guarantee in the standards any more. Who should be allowed to set the
>>> boundary? An IPv6-over-foo document? An address configuration technology
>>> such as SLAAC? 
>>
>> The last paragraph of section "2.5.1 Interface identifiers" in 4291 said:
>>
>>    The details of forming interface identifiers are defined in the
>>    appropriate "IPv6 over <link>" specification, such as "IPv6 over
>>    Ethernet" [ETHER], and "IPv6 over FDDI" [FDDI].
>>
>> The corresponding paragraph in rfc4291bis is:
>>
>>    The details of forming interface identifiers are defined in other
>>    specifications, such as "Privacy Extensions for Stateless Address
>>    Autoconfiguration in IPv6" [RFC4941] or "A Method for Generating
>>    Semantically Opaque Interface Identifiers with IPv6 Stateless Address
>>    Autoconfiguration (SLAAC)"[RFC7217].  Specific cases are described in
>>    appropriate "IPv6 over <link>" specifications, such as "IPv6 over
>>    Ethernet" [RFC2464] and "Transmission of IPv6 Packets over ITU-T
>>    G.9959 Networks" [RFC7428].  The security and privacy considerations
>>    for IPv6 address generation is described in [RFC7721].
>>
>> Don't you agree with that?
> 
> Iván,
> 
> That is the basis for Alexandre's suggestion to simply drop the mention
> of 64 from the architecture: because it's an implementation parameter.
> With my Computer Scientist hat on, I think that's the right thing to do.
> With my Pragmatist hat on, I think stating that /64 is recommended is
> a more practical approach. Stating that it's required is plain wrong.
> 
>     Brian

I agree.

Either not mentioning /64 at all or just saying it is recommended but
leaving the specifics to a "IPv6 over X" specification is better than
bolting a fixed prefix len in the standard.

Incidentally, I think this should have been deprecated in RFC 7136 when
EUI-64 was (sortof) killed.

-ivan





-- 
Iván Arce
Director del Programa STIC
Fundación Dr. Manuel Sadosky
http://www.fundacionsadosky.org.ar
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