RE: Posted a new copy of CPE Rtr draft

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

Right, Teemu.  What I was saying that if a /64 is allocated to the WAN,
then one cannot sub-delegate this /64 to the LAN interface(s) if the LAN
uses SLAAC because SLAAC has a MUST for /64 and sub-delegation would
have to go for a longer prefix.  Certainly, if no sub-delegation is
used, then as you say, use other addresses from the same prefix for LAN
- that is fine.

Hemant

-----Original Message-----
From: teemu.savolainen@nokia.com [mailto:teemu.savolainen@nokia.com] 
Sent: Friday, March 20, 2009 2:15 PM
To: bs7652@att.com; Hemant Singh (shemant); v6ops@ops.ietf.org
Cc: Wes Beebee (wbeebee)
Subject: RE: Posted a new copy of CPE Rtr draft

Hi,

In the case I look the network allocates unique /64 for the PPP link,
and thereby allows 2^64-1 or so addresses configured from that prefix
(network reserves one address for the router on the SP side of the
point-to-point link).

Do we have terminology issue here? You could indeed say all hosts
configure IPv6 address from the prefix received via WAN interface, so
from that point of view all these hosts are logically connected to WAN,
although in reality they go trough the ND proxy device.

It cannot be bridged, as the link types are different (PPP and
Ethernet), but proxied mode. 

Best regards,

	Teemu

>-----Original Message-----
>From: ext Stark, Barbara [mailto:bs7652@att.com] 
>Sent: 20 March, 2009 11:06
>To: Hemant Singh (shemant); Savolainen Teemu 
>(Nokia-D-MSW/Tampere); v6ops@ops.ietf.org
>Cc: Wes Beebee (wbeebee)
>Subject: RE: Posted a new copy of CPE Rtr draft
>
>Another alternative, might be for the router to allow the its 
>owner to put it in a bridged mode, instead of router mode. The 
>"CPE router" could still get its own IPv6 address from the 
>WAN, as a host should. But all devices in the LAN would 
>effectively just be hosts off the WAN, and there would be no 
>real LAN. There would be no ULA either. The question is 
>whether the design of the WAN would limit the number of hosts 
>that could be given addresses across that one interface. If 
>that were the case, then this wouldn't work, and the CPE 
>router would be forced to do a NAT66.
>
>In many ways, this case is very similar to that of the 
>cascaded router that isn't given a prefix.
>
>I don't think this is a corner case.
>Barbara
>
>-----Original Message-----
>From: owner-v6ops@ops.ietf.org 
>[mailto:owner-v6ops@ops.ietf.org] On Behalf Of Hemant Singh (shemant)
>Sent: Friday, March 20, 2009 1:39 PM
>To: teemu.savolainen@nokia.com; v6ops@ops.ietf.org
>Cc: Wes Beebee (wbeebee)
>Subject: RE: Posted a new copy of CPE Rtr draft
>
>Teemu,
>
>If your SP does not dole out a PD to the CPE Rtr and as you 
>say, your common case is just one /64 doled out to the WAN 
>interface with PPP.
>Ok, so if your LAN interface(s) are assigned addresses using 
>SLAAC, since SLAAC needs a /64, how can you possibly use the 
>WAN's /64 to assign addresses to the LAN interface(s)?  It's 
>not possible.  Yes, you could run a DHCPv6 server in the 
>device and then sub-delegate the /64.
>Hopefully such a DHCPv6 server sub-delegation is legal in IPv6
>standards...   
>
>Alternatively, you can use ULA for the LAN and use the CPE Rtr 
>as a router between WAN and LAN and not have anything to do 
>with ND Proxy.
>
>Hemant
>
>-----Original Message-----
>From: teemu.savolainen@nokia.com [mailto:teemu.savolainen@nokia.com]
>Sent: Friday, March 20, 2009 1:14 PM
>To: Hemant Singh (shemant); v6ops@ops.ietf.org
>Cc: Wes Beebee (wbeebee)
>Subject: RE: Posted a new copy of CPE Rtr draft
>
>Thanks for quick reply, I was ok with other things than this one:
>
>>- 7.1. In 3GPP case the /64 prefix is not only for LAN 
>interfaces, but 
>>also for the WAN interface. Thus I'd rather say:".. across 
>multiple LAN 
>>interfaces, possibly including WAN interfase as well, and the CPE 
>>router..". Then "..any two LAN interfaces.." -> "..any two 
>>interfaces..". And still later "..if any two disparate LAN 
>>interfaces..." -> "..if any two disparate interfaces..".
>>
>><hs>
>>Disagree. You are suggesting one implement ND Proxy between 
>the WAN and 
>>LAN interfaces.  For the CPE Rtr, the WAN and LAN
>>interface(s) are two different routing domains - if one can perform 
>>routing between domains, why support ND Proxy?  We are also 
>making the 
>>last sentence better in section 7.1 as follows:
>
>Yes. That is what has to be done in the link types we have to 
>support. I don't see any other way when there is just single 
>/64 received from point-to-point WAN interface (in RA) which 
>has to be enough for numbering the "CPE" itself and all the 
>devices in Ethernet LAN behind.
>Please let me know if there is a better way.
>
>Only alternative I see is to have NAT66 in CPE similar to IPv4 
>NAT we already have to share the single IPv4 address we get 
>from operator.
>
>It would be very nice if there would be DHCPv6 PD available 
>for "CPE" to ask for prefixes for LAN, but unfortunately that 
>is not always the case.
>
>I think we discussed this in IETF#73 corridor, but I have 
>forgotten details... So maybe I should write a link-type 
>specific document, which would describe this behaviour (maybe 
>corner-case from IETF point of view, but the most important 
>use-case from my point of view)? After all, I guess it is 
>better to describe it rather than have it just as 
>implementation-specific design choice?
>
>Best regards,
>
>	Teemu (I will not be able to make the v6ops meeting as 
>I have to be in shara BOF)
>
>
>*****
>
>The information transmitted is intended only for the person or 
>entity to which it is addressed and may contain confidential, 
>proprietary, and/or privileged material. Any review, 
>retransmission, dissemination or other use of, or taking of 
>any action in reliance upon this information by persons or 
>entities other than the intended recipient is prohibited. If 
>you received this in error, please contact the sender and 
>delete the material from all computers. GA625
>
>
>