RE: FW: WPD-6, WAA-8, and WAA-9 of draft-ietf-v6ops-ipv6-cpe-router-04

["Wes Beebee (wbeebee)" <wbeebee@cisco.com>]

>>>So, what is wrong with that scenario?
>>
>>Section 12.1 of RFC 3633 forbids it:
>>
>>"the requesting router MUST NOT assign any delegated prefixes or 
>>subnets from the delegated prefix(es) to the link through which it 
>>received the DHCP message from the delegating router."
>
>I know, but why?
>
>I always see a MUST NOT as something that would cause major harm or
interoperability problems. 
>But the DHCP PD RFC just says 'MUST NOT' without giving any reason what
so ever.
>
>So maybe it is time to revisit that requirement instead of using that
to force the weak host 
>model onto CPEs.

The deployment that you suggest, using an address from the PD for the
WAN interface, will cause on-link determination problems for the SP
router, and will result in lack of network connectivity to the CPE
router.  Thus, yes, there will be interoperability problems.

We need to discourage CPE routers from using the strong host model in
order to ensure that we can provide network connectivity and to allow
SP's to address the network the way that they want to.

- Wes