Re: Detailed review of Significance of IPv6 Interface Identifiers

["Fred Baker (fred)" <[e-mail]>]

On Aug 14, 2013, at 2:27 PM, Brian E Carpenter <[e-mail]> wrote:

>> * Section 3:
>>> To the extent that each method of IID creation specifies the values 
>>> of the "u" and "g" bits, and that each new method is carefully 
>>> designed in the light of its predecessors, these bits tend to reduce 
>>> the chances of duplicate IIDs.
>> 
>> Not sure what you mean. Do you mean that *if* each IID-generation method
>> were to use a different combination of "ug", colisions between them
>> would be avoided? If so, I'd argue that since there's no coordination of
>> which combinations should be used for which method, that's unfeasible.
>> For instance, traditional SLAAC uses all combinations (modulo
>> "illegal/unused" combinations of ug).
> 
> The argument is fuzzy and the sentence needs to be rewritten.
> 
> (I would actually suggest that in a pseudo-random method, now that we
> are clear that the bits have no meaning, it would be best to use them to
> provide two more bits of entropy rather than giving them fixed values.)

Good grief. If the bits don't mean anything - and they never did, since nobody ever interpreted them except in IETF dancing-on-heads-of-pins discussions - could we simply say that they are as random in value as any of the other bits in the IID are?