Re: [dhcwg] [homenet] PPP, DHCPv6 and Prefix Delegation

On Nov 19, 2013, at 3:19 PM, Bernie Volz (volz) <volz@cisco.com> wrote:

> I guess from RFC 4818, Delegated-IPv6-Prefix is used for PD. Whereas it says:
>  
>    The Framed-IPv6-Prefix attribute [4] is not designed to support
>    delegation of IPv6 prefixes to be used in the user's network, and
>    therefore Framed-IPv6-Prefix and Delegated-IPv6-Prefix attributes may
>    be included in the same RADIUS packet.
>  
> But, I’m not really clear if that ends up mapping to OPTION_PD_EXCLUDE for the Framed-IPv6-Prefix. Perhaps if the case is as in your example (Framed-IPv6-Prefix is contained by Delegated-IPv6-Prefix, but not equal) then using the Framed-IPv6-Prefix for OPTION_PD_EXCLUDE makes some sense?

3GPP system uses these in the above manner i.e. Framed-IPv6-Prefix -> what you put into RA, Delegated-IPv6-Prefix -> what you delegate via DHCPv6. And in this case what was in Framed-IPv6-Prefix goes into OPTION_PD_EXCLUDE.

- Jouni

>  
> -          Bernie
>  
> From: dhcwg [mailto:dhcwg-bounces@ietf.org] On Behalf Of Athanasios Douitsis
> Sent: Tuesday, November 19, 2013 7:40 AM
> To: Bernie Volz (volz)
> Cc: radext@ietf.org; Michael Richardson; Roberta Maglione (robmgl); dhcwg@ietf.org WG; homenet@ietf.org
> Subject: Re: [dhcwg] [homenet] PPP, DHCPv6 and Prefix Delegation
>  
> Hello (thanks for the answer),
> 
> The uplink connection between the delegating and the requesting router will be in many cases enumerated with a prefix dictated by the Framed-IPv6-Prefix value. If this uplink prefix is going to be a part of the greater prefix that will be delegated, we would in effect have to include the value of the Framed-IPv6-Prefix in the OPTION_PD_EXCLUDE.
> 
> Example, if a delegating router makes a RADIUS request and gets the following attributes in the reply:
> 
> Framed-IPv6-Prefix='2001:dead:beef::/64'
> Delegated-IPv6-Prefix='2001:dead:beef::/56'
> 
> Then the delegating router should 
> 1)send an RA in the client uplink interface with 2001:dead:beef::/64. The uplink is enumerated with that /64.
> 2)Afterwards, when requested for PD, it should reply with the 2001:dead:beef::/56 to the requesting router, but excluding the 2001:dead:beef::/64 from that /56 by putting it in the OPTION_PD_EXCLUDE.
> 
> So in effect, the Framed-IPv6-Prefix has been copied in the OPTION_PD_EXCLUDE option.
> 
> If I have misunderstood something in the RFC or the discussion, I'd be grateful if you would correct me.
> 
> Thanks very much,
> Athanasios
> 
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> On Tue, Nov 19, 2013 at 2:07 PM, Bernie Volz (volz) <volz@cisco.com> wrote:
> Why would it ever be copied into that option? That makes no sense to me.
> 
> - Bernie (from iPad)
> 
> On Nov 19, 2013, at 6:16 AM, "Athanasios Douitsis" <aduitsis@gmail.com> wrote:
> 
>  
>  
> (i.e. have a configuration option to use the Framed-IPv6-Prefix value in the prefix exclude option instead of an RA)
>  
> Correction, the above is incorrect, as has been rightly pointed.
> 
> Are there any cases where the Framed-IPv6-Prefix value will not be copied as-is in the OPTION_PD_EXCLUDE value?
> 
> 
> 
> 
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> 
> -- 
> Athanasios Douitsis
> 
> 
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