Subject: RE: [AAA-WG]: Invoking AAA during every handoff?

From: "Patil Basavaraj (NET/Dallas)" <[email-masked]>
Date: Wed, 16 Jan 2002 14:28:15 -0600

>I need some help to clarify a question. Will AAA infrastructure need to
>be invoked to reauthenticate a mobile node during every handoff when
>previous authorization is still valid, if so, then a mobile node needs
to
>include MN-AAA extension in registration request message everytime
during
>handoff ? 

It depends on whether the HO to another FA is intra or inter
domain. It is also possible that as part of the handoff process, the
context associated with the MN at the previous FA would be transferred
to the new FA and this would enable the FA to verify the authenticity
of the ongoing session and not require the MN to reauthenticate. 
Context transfer is being worked on in the Seamoby WG.

If the MN has to authenticate every time it performs a HO, the
performance of HOs becomes questionable.

>Many thanks.
>Judy

-Basavaraj

---

From: "Judy Fu" <[email-masked]>
Date: Wed, 16 Jan 2002 18:26:08 -0600

Thanks for your reply. Then do you think MN has to go through AAA everytime
there is a handoff if without context transfer? The AAA round trip delay may
not be a big issue since MN has to send binding update to HA everytime it
does HO anyway as specified in "Mobility support in IPv6" draft. Unless
there is way to eliminate the binding update/ack round trip delay for HO.

In "draft-ietf-aaa-diameter-mobileip-08.txt" section 1.3, support for mobile
IP handoffs, it says" Many FA do not communicate, which makes it quite
difficult for AAA information to be exchanged between these entities.
Therefore, it MUST be assumed that a FA is not aware that a registration
request from a mobile node has been previously authorized. The first
registration request from a mobile node will therefore cause an AMR to be
sent to its AAAF". It seems to me it means by default (without context
transfer or other enhancement) AAA will be invoked every time there is a
handoff. In addition, if without invoking AAA, i.e. there is no path of new
FA-AAAF-AAAH, it is not clear how the new FA report accounting data of the
MN to AAA infrastructure. I wonder if I understand correctly.

Thanks again.
Judy