Subject: Re: [mobile-ip] Fast Handover document revision

From: Rajeev Koodli <[email-masked]>
Date: Tue, 11 Feb 2003 16:30:22 -0800

James Kempf wrote:

  > 1. Securing the Fast Binding Update. I would like folks to provide
  >     input on this. What should we do ?
  >

  Sorry to sound like a broken record, but if the signaling is confined
to being
  just between the current AR and MN, security for IPv6 Neighbor
Discovery as
  outlined in RFC 2461 and RFC 2462 can be used.

Do you mean IPSec ? Who distributes the keys ? Or, do you mean
punt the problem ?

  Unless I'm missing something, if the signaling is sent back to the
PAR, as the
  current FBU proposal does, I don't see how the signaling can be
secured without
  introducing another mechanism. The two ways of securing BUs currently
accepted
  are a) Return Routability to CNs or b) a specialized IPsec security
association
  with the HA. Leaving aside the question of how the MN gets a global
address for
  PAR in the first place, neither of these are appropriate in this case
IMHO.

Whatever mechanism establishes the SA between the MN
and the AR should provide the means to secure the FBU regardless
of from where it is sent.

I am trying to assess what mechanism(s) we should consider, including
whether it needs to be devised for FMIPv6 at all..

  > 2. Regardless of whether FBack is received or not, the MN always
sends
  >     the same message to the new router. This message
  >     - confirms new CoA
  >     - announces the MN's presence to the new router
  >
  >     The message itself would be a refined FNA, as an option in the
  > Router
  >     Solicitation message. The response would be a NAAck option in
the RA
  >
  >     message.
  >
  >     What do folks think about this ?
  >

  I think this the RS/RA should be reused for this purpose, as it cuts
down on the
  signaling and accelerates the MN's configuration on the new link.

Ok.

  > 3. Based on the discussion prior to the last IETF and
  >      during the last IETF, I would like to allow PrRtSol and PrRtAdv

  >     exchange to be possible ahead of the handover. So, for instance,

  >     a MN may exchange these messages upon attaching to a router.
  >     This means fewer messages during handover, shorter time for
  >     which the handover state needs to be managed and better chances
  >     of anticipating a new CoA. Also, the binding at the old router
is
  > created
  >      upon processing the FBU, and is more consistent with the base
  >      Mobile IPv6 spec.
  >     Please acquaint yourself with the discussion on the ML and the
  >     presentation slides before you comment :-)
  >

  There are issues with anticipated address configuration, as discussed
in a
  separate email.

I have replied to that e-mail.

Regards,

-Rajeev

              jak

---

From: "James Kempf" <[email-masked]>
Date: Wed, 12 Feb 2003 08:31:21 -0800

> Do you mean IPSec ? Who distributes the keys ? Or, do you mean

IPSec AH with cryptomethod based on public key, currently being defined by SEND
(see http://www.ietf.org/html.charters/send-charter.html for SEND charter).
Alternatively context transfer and AAA key distribution could be used, as is
being proposed in 802.11i.

> of from where it is sent.

If the MN can get a global address for the PAR, right?

> whether it needs to be devised for FMIPv6 at all..

I think we should try to avoid this. New security mechanisms are hard to invent,
and even harder to prove secure, and therefore I think it would make more sense
to rearrange the signaling so that we can reuse existing methods if at all
possible. There are a couple good candidates if we run the signaling between the
MN and it's current AR.

            jak

---

From: Rajeev Koodli <[email-masked]>
Date: Wed, 12 Feb 2003 10:11:13 -0800

> being proposed in 802.11i.

AH ? Ok. Any idea when this is supposed to be available ? I agree
that if there is a mechanism available, we should use it. Simplifies
my task :-). I am not sure if we have one now..

> If the MN can get a global address for the PAR, right?

Yes.

> possible. There are a couple good candidates if we run the signaling between the

I agree to re-using "proven" mechanisms. However, if the
applicability is limited to on-link signaling (and I cannot imagine
why), then we need to take another look. But, a more pressing
concern is when are these available ? Placing a dependency
comes at a price (read: trace locus of MIPv6 security).

-Rajeev

---

From: "James Kempf" <[email-masked]>
Date: Wed, 12 Feb 2003 11:04:45 -0800

> my task :-). I am not sure if we have one now..

The plan is to have an initial draft for SEND by the SF 00 deadline. I don't
know what is happening with 802.11e, but I'm told there were proposals for key
distribution using CT at the last meeting.

            jak