RE: Comments on draft-wbeebee-ipv6-cpe-router-01.txt

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

See RFC4241 and section 2.8 that says:

[To achieve this requirement, for example, once the prefix
   2001:db8:ffff::/48 is delegated, the CPE must reply to the ICMPv6
   Echo Request destined for 2001:db8:ffff:: any time that IPV6CP and
   DHCPv6-PD are up for the upstream direction.  Because some
   implementations couldn't reply when 2001:db8:ffff::/64 was assigned
   to its downstream physical interface and the interface was down, such
   an implementation should assign 2001:db8:ffff::/64 for the loopback
   interface, which is always up, and 2001:db8:ffff:1::/64,
   2001:db8:ffff:2::/64, etc., to physical interfaces.]

NTT's ADSL deployment is already using a Loopback interface and why.

Hemant  

-----Original Message-----
From: ichiroumakino@gmail.com [mailto:ichiroumakino@gmail.com] On Behalf
Of Ole Troan
Sent: Tuesday, July 15, 2008 6:56 PM
To: Stark, Barbara
Cc: Hemant Singh (shemant); v6ops@ops.ietf.org; Antonio Querubin
Subject: Re: Comments on draft-wbeebee-ipv6-cpe-router-01.txt

Barbara,

> I disagree that if the loopback interface is not configured "you will 
> have to use the Numbered model of our document and assign a global 
> IPV6 to the WAN interface". Just to be sure, I think you're saying 
> that the CPE router will need to get a global IPv6 address via SLAAC 
> or stateful DHCPv6, from the access network. I do not see any reason 
> why the CPE router cannot use one of the addresses from its assigned 
> prefix. Since we are definitely considering using the "unnumbered 
> model", and we have no loopback interface in our devices (and have no 
> intention of having them), I think I'm going to have to try to get a
second opinion on this.
> Does anyone else have an opinion on whether or not the "unnumbered 
> model" will only work in the presence of a loopback interface?
>
> By the way, I've never seen such a loopback interface in any mass 
> market retail CPE routers. To me, the capabilities found in such mass 
> market routers should be the benchmark for "very normal". I'm also not

> familiar with it in DSL routers. DSL routers are also "very normal",
worldwide.
> I've been trying to search the Internet for products that include this

> interface, and all I can find are Cisco products with IOS. I'm curious

> as to whether any other vendors implement this interface, and, if so, 
> on what sorts of mass market products.

the loopback interface is a red herring. the unnumbered model will work
just fine without it.

/ot