Subject: RE: [nemo] Aggregated prefixes and Proxy ND

From: "Pascal Thubert \(pthubert\)" <[email-masked]>
Date: Thu, 2 Sep 2004 15:08:13 +0200

Hi Ville :)

> Since the HoA will never be on the same link as the HA, should the HA
> still do the DAD probe and perform Proxy ND for it? Then again, I
guess
> there isn't any harm in doing that, so perhaps it's ok for the HA to
> always do Proxy ND for the MR.

I'm not sure that the nemo basic support spec should say anything about
that; but the home network model, definitely, because this depends no
the model being deployed.

NEMO has extended the MIP concept of Home. Depending on the model, Home
might be applied on a virtual or a physical link. Or Home might just be
an aggregation that is declared to the HA configuration in terms of
routes. What is supported depends on the implementation. If Home is not
applied on a physical link, then obviously there is no DAD.

Conceptually, there is a movement out of ND dependencies. MIP6 is based
on ND, NEMO has remnants of that when the home link is applied on a
physical link, HAHA protocol gets rid of that completely.

In fine, the idea is that the home address would end up being used as a
unique ID, and NEMO could a route to the MNP over a tunnel that ends at
the Care-Of Address, the whole thing being correlated by the home
address. The fact that the home address is on a home link, on an MNP, or
just any form of unique ID would be inconsequential.

But for now with nemo basic support: the Home Addresses being part of
the MNPs is not a problem is the link is virtual or if Home is
configured outside of a link for your implementation - as opposed to
MIP6 where home is on a link. 

If Home has to be configured on a physical link for your HA to recognize
it as home, then yes you may have to perform DAD. This is needed at
least in the case of aggregated home network, if your implementation
supports it. If the MR is at home, the MR bridges the packets to the
MNPs and yes, if the MR is at home, then, virtually, all the MNNs are on
the home link, so, in particular, the MR home address can be reached for
DAD.

In the case of the extended home network, if the MR Home Addresses is
taken from the MNP, the home address is not expected on the home link in
any case, and as you point out, DAD would useless. But then the MR can
never come back home, either. In my mind, the expectation for extended
home network is that you take the home address from the home link, not
from the MNP.

Pascal