Re: Last Call: <draft-ietf-6man-rfc4941bis-10.txt> (Temporary Address Extensions for Stateless Address Autoconfiguration in IPv6) to Proposed Standard

[Alexandre Petrescu <[e-mail]>]

Le 12/09/2020 à 07:36, Fernando Gont a écrit :
> On 10/9/20 08:35, Alexandre Petrescu wrote:
>>
>>
>> Le 10/09/2020 à 13:26, Lorenzo Colitti a écrit :
>>> Having read this document again, I have the following concerns.
>>>
>>> 1. I think it should not include section 3.3.2. The reason is that it
>>>  needlessly suggests an algorithm that is much more complex than
>>> simply using an existing random number generator which all nodes
>>> likely already have.
>>
>> I object to that I-D paragraph at least because it says this "SHOULD
>> produce an output of at least 64 bits."  It should be of a more variable
>> length.  It is not 'at least 64bit'.
> 
> Huh?
> 
> SLAAC IIDs are currently required to be 64-bit long, hence the output 
> should be of at least 64 bits -- if the output is 64-bits, you take all 
> of them, whereas if it's more that 64-bits, you discard the exceeding bits.

I agree that IPv6-over-foo IIDs part of SLAAC requires that to be 64bit 
long.

And I maintain it is a wrong requirement.

The requirement should be that is a variable length.  An IID of length 
45 should work in SLAAC as much as an IID of length 72.  And 
incidentally 64, some times.

Some implementations do work the way I say it (openbsd IID length 45 or 
72 works).  Some implementation is under development in linux to make 
that work too.  They are different implementations but achieve the same 
thing.

>> I do not oppose to the existence of that section 3.3.2.  But how would
>> it cope with other generated Interface Identifiers, like HIT (Host
>> Identity Tag) or ORCHIDs.  These are too RFCs on the Standards Track.
>> They too are generated by a crypto function, they too are 64bit length.
>>   Still they are different than this F().
> 
> This is orthogonal to this document.

Hmm... orthogonal, yes, but there could be an ideal goal that RFCs at 
IETF make sense all together, I think.  If HIP protocols considers 
always that IID must be 64, but other RFCs no, then there is obviously a 
need to try to make sense all together.

True, the task might seem huge, and so we call it orthogonal: it would 
be hard to climb a vertical :-)

Alex

> 
> Thanks,