RE: Posted a new copy of CPE Rtr draft

[<teemu.savolainen@nokia.com>]

Hemant,

Well, the RFC4389 describes this functionality of sharing the prefix between WAN and LAN.

I don't see how the ULAs could be used for global communication by devices in LAN.

Best regards,

	Teemu

>-----Original Message-----
>From: ext Hemant Singh (shemant) [mailto:shemant@cisco.com] 
>Sent: 20 March, 2009 10:39
>To: Savolainen Teemu (Nokia-D-MSW/Tampere); 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)
>