Subject: [AAA-WG]: HA sending AMR

From: Sivasundar Ramamurthy <[email-masked]>
Date: Fri, 22 Feb 2002 14:50:04 -0800 (PST)

Hello,

This is regarding AAA Mobile IP application.

Consider the scenario when a MN returns home and sends a registration
request to the HA for deregistration. Also, the MN-HA key has expired
and the MN makes the deregistration request a AAA request. I am
assuming that no standards prevent the MN using a AAA request for
deregistration.

While it is clear that the HA can send an AMR for a AAA request with a
co-located COA, it is not clear as to what the HA should do in the
de-registration case. And if the HA "can" send an AMR, current
standards imply that the registration would go through the
AMR-HAR-HAA-AMA cycle, all exchanged between the AAAH and the HA. (It
seems like the AAAH directly sends an AMA for an AMR only if the
co-located bit is set in the mip-feature-vector).

I am guessing that the Mobile IP draft implicitly addresses this case
and that going through AMR-HAR-HAA-AMA cycle is the implied solution.
If so, can we optimize it similar to the co-located COA MN and have
the HA and the AAAH just exchange AMR and AMA messages (maybe an
extra bit in the feature vector).

If going though the AMR-HAR-HAA-AMA cycle is not the implied
solution, can someone tell me how this case is handled by the HA (and
the AAAH)?

If the draft does not cosider this scenario at all and all the
"implied solution" is my imagination, can we specify what the HA
should do in this case?

thanks!

Siva

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From: Tony Johansson <[email-masked]>
Date: Fri, 22 Feb 2002 15:33:16 -0800

Hi Sivasundar,

> assuming that no standards prevent the MN using a AAA request for

In the scenario that you describe above the MN Keys has expired, which
also means that the MN knows that if it doesn't issues a re-registration
the MN will be de-registered, since the HA will issue an STR to the AAAH.
So why would the MN issue a de-registration in this case?

/Tony

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From: Sivasundar Ramamurthy <[email-masked]>
Date: Fri, 22 Feb 2002 16:15:48 -0800 (PST)

Hi Tony,

> So why would the MN issue a de-registration in this case?

So the MN need not bother to de-register if the key to the HA is
expired, since the registration would have been terminated by the HA
anyway...that makes sense.

Some MN(s) might have a policy to re-request keys much before the
keys expire, like re-registering before the previous registration
expires. For such MN, it is possible that it is deregistering when
its time to re-request keys - a AAA de-registration request!
Even in such cases the MN should probably not send the request
and simply let the registration terminate on its own...

And as far as the HA is concerned, it need not bother to process a
de-registration AAA request in case some MN unnecessarily sends it
(even with a co-located COA). It will drop such requests and will
simply allow the registration to terminate "on its own" (registration
lifetime or key lifetime expiration).

Thanks for the clarification!

Siva

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From: "Fredrik Johansson" <[email-masked]>
Date: Mon, 25 Feb 2002 10:54:26 +0100

Hi,

see comments below

/Fredrik

>expires.

It should, otherwise it will lose its connection and the next registration
will be seen as a new registration.

>For such MN, it is possible that it is deregistering when

In this case, it will still have its MN-HA SA and can add both the MN-HA
authentication extension and the mn-aaa authentication extension. This will
enable the HA to make a policy decision, since it can authenticate the mn,
the HA can send a STR to the AAA-H and a registration reply to the mn, thus
the mn is deregistered.

>and simply let the registration terminate on its own...

why not, the mn should always send a deregistration when it returns home.

/Fredrik