Subject: [Mip6] Addition of SA after 1st return routability

From: "Prashant Ramaswamy" <[email-masked]>
Date: Mon, 20 Oct 2003 12:00:52 +0530

Hi,

I am doing a study of performance with secure signaling in Mobile IPv6. 

I had a query: Considering the scenario where the Mobile node moves from
one link to another, how does the MN send updates to the CNs to whom it
was earlier talking. Does it start the return routability test again (as
per current draft).

Further, suppose after getting the Binding Update, I also instruct the
CN to add a security association to its database (in some way), then it
will be quite easy to send further updates. The MN will also update its
SPD with SA=Home Address, DA=CN, use this SA. What are the risks
involved in this? I feel this will help in efficiency because the major
delay currently is when the MN moves from one foreign network to
another. 

Hope I am not missing anything trivial.

Thanks
Prashant

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From: Erik Nordmark <[email-masked]>
Date: Tue, 21 Oct 2003 14:21:10 +0200 (CEST)

> delay currently is when the MN moves from one foreign network to

One security concern that was taken into account for the base MIPv6 security
of BUs to the CN was 3rd party flooding attacks.
If the MN lives on a bandwidth limited path (e.g., 56kbps)
and the CN does not (1 Gbps), then  the ability for the MN to
say "please send my packets to this CoA" without the CN verifying
that the MN is in fact present at that CoA would introduce DoS flooding
capabilities of 1 Gbps for the MN which only has 56 kbps bandwidth.
This is part of the reason for the CoTI/CoT exchange.

Having a SA between the MN and CN doesn't remove this concern.
It might make sense to consider the security implications of an "optimistic"
mode where CoTI/CoT can happen in parallel with the BU taking place and if, 
after a few seconds, the CoT doesn't arrive the binding would be undone.

  Erik