Re: [netext] Chair review of I-D: draft-ietf-netext-pd-pmip (05)

Pete,

On Nov 20, 2012, at 10:18 PM, Peter McCann wrote:

> Hi, Jouni,
> 
> What if the new MAG cannot connect back to the old LMA?  How does the
> MR find out that its delegated prefix is no longer routable?

In that case your PMIP session goes down.. and the MR sees it as a change
of the link. In that case MR does what any DHCP client is supposed to do
i.e. verify whether its prefixes are still valid on the new link using a
confirm/reply exchange.

- JOuni

> 
> -Pete
> 
> 
> jouni korhonen wrote:
>> 
>> Pete,
>> 
>> On Nov 20, 2012, at 6:50 PM, Peter McCann wrote:
>> 
>>> Basavaraj Patil wrote:
>>>> 
>>>> 5. How does the MAG know that it needs to allow forwarding of packets
>>>> via the PMIP6 tunnel for packets with SRC address that are derived
>>>> from the delegated prefixes? Its not clear if there is added
>>>> functionality needed at the MAG to accomplish this.
>>> 
>>> I think there are potentially some deeper issues here.
>>> 
>>> The MN sees the original MAG as its "delegating router".  When the
>>> MN changes to a new MAG, there is no good way to tell that the
>>> delegated prefixes are still routable to the link.  The delegating
>> 
>> This is what the I-D is about.. That's we got the new signaling in
>> place and the handover case described in Section 3.4.3.
>> 
>>> router has become unreachable.  The new router may send an RA that
>>> advertises the original link prefix, and so the MN can tell that its
>>> SLAAC unicast addresses are still valid on the link.  However,
>> 
>> When the MR (i.e. in RFC5213 terminology the MN) does a handover, the
>> prefix used between the MR-MAG stays the same as usually provided by
>> PMIP6. Section 3.4.3 the describes what the MAG has to do in order to
>> know the existing delegated prefixes and set the forwarding state.
>> 
>>> RFC 3633 says that the delegated prefix is NOT advertised on the
>>> link between the delegating router and the requesting router.
>> 
>> And they are not. The delegated prefixes are used on the downstream
>> interfaces of the MR, not on the MR-MAG link. If the prefix used on
>> the MR-MAG link is part of the delegated prefix, then the MR has to
>> use RFC6603.
>> 
>>> Therefore, there is no way for the MR to determine whether it can
>>> still use the delegated prefixes, other than perhaps re-running
>>> DHCPv6-PD on the new link.
>> 
>> From MR point of view nothing changed. So what is the issue?
>> 
>> - Jouni
>> 
>> 
>>> 
>>> -Pete
>>> 
>>> 
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> 
> 
> 