Re: CPE router learning DNS servers - comment on draft-ietf-v6ops-ipv6-cpe-router-03

[Ole Troan <ot@cisco.com>]

Dan,

to make sure this has been answered.

>> The L-6 requirement is a LAN-side (DHCPv6 Server) 
>> requirement.
> 
> You're right; my misread.
> 
>> However, since SLAAC is the expected method for address config in 
>> the LAN, and support for DHCPv6 DNS_SERVERS option is a MUST (and 
>> other options is a SHOULD), I think that the MAY statement for 
>> stateless DHCPv6 support might not be completely consistent.
> 
> Agreed - we certainly need a way for the hosts to learn their
> IPv6 DNS servers.  And it should agree with RFC4339 and RFC5505
> (neither of which are cited by draft-ietf-v6ops-ipv6-cpe-router-03).

these changes should hopefully clear the inconsistency:

   L-10:  The IPv6 CE router MUST support a DHCPv6 server capable of
          IPv6 address assignment according to [RFC3315] OR a stateless
          DHCPv6 server according to [RFC3736] on its LAN interfaces.

   L-12:  The IPv6 CE router MUST support providing DNS information in
          the DHCPv6 DNS_SERVERS option [RFC3646].


with regards to RFC4339, I consider that historic at this point.
as for RFC5505 I see that more as guidelines for protocol developers. we are trying hard to invent nothing in this draft, so I'm not sure it is relevant to cite 5505 either.

>> As for the WAN-side (DHCPv6 client), there's currently no mention of
>> stateless DHCPv6. It does seem implied by other requirements that
>> describe support for SLAAC + the ability to get other config info via
>> DHCPv6. It might be good to be more explicit on this.

since we have a MUST on a stateful DHCP exchange on the WAN interface I don't see the purpose of mentioning  the so-called stateless variant.

cheers,
Ole