Re: I-D Action: draft-mishra-6man-variable-slaac-01.txt

[Philip Homburg <[e-mail]>]

>How does this work if the router expects hosts to use shorter IIDs but
>hosts in fact use standard 64 bit IIDs? As far as I can see, SLAAC,
>DAD and default address selection will only work correctly if all
>nodes on a given link agree about the prefix and IID lengths. For
>all existing devices, the baked-in code assumes that both are 64.
>
>If a 64 bit node wants to send to a destination with the same
>64 bit prefix that is in fact off-link because the on-link prefix
>is actually supposed to be /68, what happens?

I don't expect any problems here. In the past I did advertise a /96 prefix
om my network and nothing bad happened.

What is supposed to happen is that a host only configures a SLAAC address if
the IID length and the prefix length add up to 128. So existing hosts should
just ignore anything that is not a /64. No address, no need to participate in
DAD.

As for an on-link prefix, this is completely separate from SLAAC. Today
you could have an on-link /68 and use that for DHCP IA_NA and all hosts
should be able to use that.

My personal opinion on this draft is that we spend enough discussing this,
The problem statement doesn't seem to contain new information. 

Of course it is worth looking (probably in v6ops) if there are clear gaps
in our exiting solutions for distributing prefixes.