Re: CPE router draft: Default route and WAN interface provisioning

[Ole Troan <otroan@employees.org>]

Fred,

>> as the editor of the draft-ietf-v6ops-ipv6-cpe-router let me bring the following questions to the
>> list.
>> 
>> the IPv6 CE router WAN interface needs to acquire addresses i.e behave like a host if one follows the
>> definition in RFC4862. it forwards traffic out this interface so it is also a router.
>> we don't want to redefine the host/router definitions in 4861/4862. for the purposes of address
>> assignment of a router interface, is this text acceptable and clear:
>> 
>>   "When the router is attached to the WAN interface link it must act as
>>   an IPv6 host for the purposes of stateless or stateful interface
>>   address assignment ([RFC4862]/[RFC3315]).  The router acts as a
>>   requesting router for the purposes of DHCP prefix delegation
>>   ([RFC3633])."
> 
> Why does it need a non-link-local address on the WAN
> interface? If it is going to act as a requesting router
> in DHCP prefix delegation, it can get non-link-local
> addresses to assign to its other interfaces.

you can of course redefine the problem and say that they link should have no global addresses.
it is an operational choice if one wants to number it or not, and in any case one would want to cater for the case where both hosts and routers are connected to the SP router which then doesn't have to behave differently for which device connects to it.

>> the IPv6 CE router also needs to set up routing. rfc3633 does not say anything about routing. there
>> are multiple ways the IPv6 CE router's routing table could be set up. we're suggesting to include
>> this requirement as a last resort catch to get a default route installed:
>> 
>>   "WPD-3:  Absent of other routing information the IPv6 CE router MUST
>>           use Router Discovery as specified in [RFC4861] to discover a
>>           default router and install a default route in its routing
>>           table with the discovered router's adddress as the next-hop."
>> 
>> these are the last remaining issues we have with the CPE router draft before we'd like to publish a
>> revision which I hope should be ready for WG last call.
> 
> If the IPv6 CE uses Router Discovery as specified in
> [RFC4861], then it will send RS and any default routers
> that hear it will set IsRouter to FALSE in the
> corresponding neighbor cache entry.

that is correct. do you see any problems with that?

cheers,
Ole