Re: I-D Action:draft-ietf-v6ops-ipv6-cpe-router-02.txt

[Ole Troan <otroan@employees.org>]

Hiroki,

> (Section 4.1)
>  | When the router is attached to the WAN interface link it must act as
>  | an IPv6 host for the purposes of IPv6 interface initialisation, ND
>  | Router Discovery, Prefix Discovery and interface address assignment
>  | ([RFC4861]/[RFC4862]).  The router acts as a requesting router for
>  | the purposes of DHCP prefix delegation ([RFC3633]).
>
>  I think this description is unclear whether the router must "act as
>  an IPv6 host" on WAN side even after interface initialization or not.
>  More specifically, 1) we should set or not the R-bit in Neighbor
>  Advertisement messages on WAN side, and 2) the WAN interface can
>  respond to Router Solicitation messages or not.

for the purposes of SLAAC, router discovery etc it should always act
as a host on the WAN interface. it should not reply to RS messages nor
set the R-bit in NAs.
I'll take a stab at better text, but feel free to suggest something.

>  IMO when the CE router is working as an IPv6 router (IsRouter flag in
>  RFC4861 is enabled) after the provisioning, the IPv6 router behavior
>  of Neighbor Discovery makes sense.  If the IP forwarding is disabled
>  for some reason, acting as a host on WAN interface link would be
>  reasonable for re-initialization.

IP forwarding is enabled on the WAN interface. it is only for address
assignment that the host functions of RFC4861/4862 are used. the
interface is acting as _both_ a router and a host on the interface.

>  Anyway, the description in Section 4.1 can be improved by making this
>  point (when it must act as a host and when it must act as a router)
>  clear.

it acts as both. again, feel free to submit better text.

cheers,
Ole