Subject: RE: [Mip6] review of draft-ietf-mip6-bootstrapping-split-00.txt

From: "Kilian Weniger" <[email-masked]>
Date: Tue, 27 Sep 2005 15:58:54 +0200

Hi all,

draft-ietf-mip6-bootstrap-ps-03 says that local HA assignment has been
mentioned as one approach to provide efficient routing and location
privacy, but unfortunately there is no reference. Did the authors refer
to draft-koodli-mip6-location-privacy-solutions-00.txt, which proposes
reverse tunneling as one solution to prevent the disclosure of MN's CoA
and, thus, location to CN?

My question is if and how local HA assignment as described in
draft-ietf-mip6-bootstrapping-split-00.txt can provide location privacy.
If a MN gets assigned a local HA, it changes its HoA and updates DNS. It
is true that the CoA is not disclosed to CN if MN uses reverse tunneling
to the local HA. But IMO location privacy support might be broken, since
the new HoA now contains location information and is publicly available
in DNS, i.e., other nodes (including CN) can derive the (approximate)
location of MN by requesting MN's HoA from DNS. By periodically querying
DNS, others can even track MN's movement. I agree that the accuracy of
the location might be relatively low, depending on "how local" the local
HAs are and how quick the MN changes to new (i.e., closer) local HAs.
But if the accuracy is low because the MN has not switched to the
closest local HA, it is likely that the routing efficiency is not good,
too.

An alternative solution to this problem is to reverse tunnel to local
HAs, but keep the HoA of MN unchanged. This approach is, e.g., proposed
in draft-weniger-rota-00.txt.

BTW, shouldn't the QNAME be set to "_mip6_ipv6.example.com" instead of
"mip6.example.com" in the DNS lookup by service name example in section
5.1.2 of draft-ietf-mip6-bootstrapping-split-00.txt? 

Regards,

Kilian

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From: Vijay Devarapalli <[email-masked]>
Date: Tue, 27 Sep 2005 10:22:54 -0700

> closest local HA, it is likely that the routing efficiency is not good,

the MN could refrain from asking the HA to do the DNS update.
as described in draft-ietf-mip6-bootstrapping-split-00.txt,
the HA does not update the DNS entry for the MN unless the
MN requests it.

> 5.1.2 of draft-ietf-mip6-bootstrapping-split-00.txt? 

yes.

Vijay