RE: draft-wbeebee-ipv6-cpe-router-04 comments

["Hemant Singh (shemant)" <shemant@cisco.com>]

>I don't see in the Unnumbered Model where the CPE is required to send  
>any RS, nor do I think it's safe to assume that CPE routers will ever  
>receive any unsolicited multicast RA announcements.

When a network interface on any router inits itself and performs any
"address acquisition", the network interface of the router is acting as
a host.  According to RFC 4861, section 4.1, the text says that hosts
send RS to solicit an RA quickly.  Even in the Unnumbered model, the CPE
Router will use a LAN interface or Loopback interface IPV6 address to
source packets - this is equivalent to the WAN interface "acquiring" an
address.  However, it is loose.  We can certainly mandate in the
Unnumbered section that the WAN interface MUST send an RS. 


>Be careful here.  RFC4191 MoreSpecificRoute messages, properly formed,

>are neither rogue nor accidental.
>So.  Are CPE routers required to process RFC4191 MoreSpecificRoute  
>options, or are they required to ignore them?  Or does this draft even

>want to take a position?

This draft takes the position taken by RFC 4861 which in section 4.2
says
[Future versions of this protocol may define new option types.
 Receivers MUST silently ignore any options they do not recognize
 and continue processing the message.]

Cable CMTS and DSLAM nodes at the SP edge have no need to be multi-homed
which is one reason to consider RFC 4191.  Also if you look at the "IPv6
Node Requirements RFC 4294-bis", this document does NOT mention RFC 4191
and hence so we won't either.  Is there a compelling reason for the CPE
Rtr to support RFC 4191?  If there is, you have to take it up first with
the "IPv6 Node Requirements RFC 4294-bis" folks.

Hemant