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RE: I-D Action:draft-ietf-v6ops-ipv6-cpe-router-03.txt
>> (a) The IPv6 CE router MUST support DHCP prefix delegation
>> requesting router behavior as specified in [RFC3633]
>> (IA_PD option).
>> (b) The IPv6 CE router MAY indicate as a hint to the
>> delegating router the size of the prefix it requires.
>> If so, it MUST ask for a prefix large enough to assign
>> one /64 for each of its interfaces rounded up to the
>> nearest nibble and MUST be configurable to ask for more.
>> The IPv6 CE router MUST be prepared to accept a
>> delegated prefix size different from what is given in
>> the hint.
>This may be getting a bit to fuzzy. I'd prefer something more along the lines of the original statement.
>Assuming the intention is to ensure that each IPv6 interface in the CE router can be configured with a
> /64, should the requirement not be that the CE router does not request (or hint for) a prefix that is
> too small? (without going into saying how large it actually should be)
> Maybe this has been discussed before, but what is the desired behaviour of the CE router in case the
> delegated prefix actually is too small to assign a /64 to each of its interfaces?
I suspect that the behavior for a too small prefix would be vendor-dependent as I don't think that we could end up with recommending a specific behavior that would pass IETF consensus. However, I think that asking for a prefix large enough to do SLAAC, even if you don't get it, is behavior that is completely reasonable and the right thing to do - but shouldn't be mandated. Stating this hint in this document is a heads-up to service providers to expect that some CE routers may have this behavior. Therefore, I agree with the text of WPD-1b as is - subject to possibly breaking up MAYs and MUSTs as we're doing elsewhere in the document.