Re: Updated IID length text

[Fernando Gont <[e-mail]>]

On 01/19/2017 12:04 AM, Lorenzo Colitti wrote:
> On Thu, Jan 19, 2017 at 11:46 AM, Manfredi, Albert E
> <[e-mail] <mailto:[e-mail]>> wrote:
> 
>     Now that we have moved away from using the MAC address for SLAAC,
>     it's not clear to me why a host cannot wait for a RA, and then
>     decide on how many IID bits to use, based on the prefix length(s)
>     advertised by the router.
> 
> 
> The reason it can't do that is that in practice SLAAC only works well if
> the probability of collision is negligible. Even reducing that from 64
> bits to 48 bits impacts that substantially.

Oh, I love this. So you are a fan of still doing modified EUI-64 with
randomized MAC addresses (which wastes 18 bits, including the 16 bits
that are wasted with embedding 0xfffe), and now you say that using /48
would impact things substantially?

This can't possibly make sense.

If you do /48 + RFC7217, you get even two ore bits of entropy than if
you do Modified EUI-64 with random MAC addresses (a flowed scheme that
you've been fighting for for a while now)

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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