FW: new draft on IPv6 CPE router available for review

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

For some reason, Hemant is unable to post to v6ops even though he is subscribed to it.  Therefore, I'm forwarding this e-mail.

- Wes 

-----Original Message-----
From: Hemant Singh (shemant)
Sent: Tuesday, July 01, 2008 11:38 AM
To: 'Remi Denis-Courmont'; Wes Beebee (wbeebee)
Cc: v6ops@ops.ietf.org
Subject: RE: new draft on IPv6 CPE router available for review

Remi,

We missed seeing RFC4605 - thanks for its reference. We can shorten section 6.1 to be very brief showing how RFC4605 will work between the WAN and LAN interface(s). Further, right now we don't have strong language in the draft for prefix sub-delegation, but we can consider making it so for prefix sub-delegation - our preference is prefix sub-delegation. 

As for mcast, the CPE router maintains a Mcast Forwarding Information Base (MFIB) that maps mcast group memberships to output LAN interface(s). When a mcast packet on the CPE router downstream needs forwarding from WAN interface to a LAN interface, the MFIB is looked up for packet forwarding. Details on how the MFIB is populated are given in the mcast section. Maybe we can add a picture showing CPE router conceptual blocks for mcast and also demonstrate mcast forwarding with an example if more folks don't understand this section.

We do have v6-to-v4 and v4-to-v6 NAT in mind even though we haven't added it to the CPE router draft. We didn't write those sections yet because some functionality spans the CPE router IPv4 features when our draft currently says any IPv4 feature is out of scope for the document. We have to massage some text in the document and then write a NAT section. We don't plan on recommending any v6-to-v6 NAT for the CPE router since IPv6 standards also do not recommend it.

Thanks.

Hemant & Wes

-----Original Message-----
From: Remi Denis-Courmont [mailto:rdenis@simphalempin.com]
Sent: Tuesday, July 01, 2008 5:37 AM
To: Wes Beebee (wbeebee)
Cc: v6ops@ops.ietf.org; Hemant Singh (shemant)
Subject: Re: new draft on IPv6 CPE router available for review


On Mon, 30 Jun 2008 13:14:22 -0400, "Wes Beebee (wbeebee)"

<wbeebee@cisco.com> wrote:

> Please review this draft.

>  

> http://www.ietf.org/internet-drafts/draft-wbeebee-ipv6-cpe-router-00.t
> xt



Section 6.1 seems to be a reinvention of RFC4605. I am also confused as to

how multicast should be forwarded (or not) between the multiple LAN

interfaces, if there are more than one.



Also, IMHO, the document lacks (adequate) guidance on the chaining of CPEs.

This is a real life problem, which in IPv4 is typically "solved" through

layering of NATs. It might not be wise to ignore the issue in IPv6. I guess

one solution is to have the CPE revert to bridging (but loops may occur),

while another solution is to _mandate_ support for prefix sub-delegation.



-- 

Rémi Denis-Courmont

http://www.remlab.net