Subject: [AAA-WG]: AAA Registration Keys for Mobile IP?

From: "Martin Julien (ECE)" <[email-masked]>
Date: Fri, 16 Mar 2001 12:29:48 +0100

Hi,
 
From reading the "AAA Registration Keys for Mobile IP" document (draft-ietf-mobileip-aaa-key-04.txt), I was wondering if you could help me understand the sections 6 and 7? The thing is that I don't see exactly what they can be used for. For example, is the MN-FA Key Request (section 6) sent in the MIP Registration Request in order to suggest a SPI between the MN and the FA? Then, I guess that the FA can suggest it to the AAAH in the AMR using the MIP-FA-MN-Preferred-SPI AVP, right? I guess the FA can also suggest a SPI between the FA and the HA using the MIP-FA-HA-Preferred-SPI AVP, right? However, if the MN sends a MN-HA Key Request (section 7) including a preferred SPI to be used between the MN and the HA, how can it be sent to the AAAH? It does not seem to exist any AVP for that in the Diameter Mobile-IP protocol. Can that subtype be used at all within the AAA infrastucture meaningfully?
 
Also, note that in section 7, it is referred to the foreign agent instead of the Home Agent???
 
Regards,
Martin

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From: Patrice Calhoun <[email-masked]>
Date: Fri, 30 Mar 2001 11:35:02 -0800 (PST)

> From reading the "AAA Registration Keys for Mobile IP" document
> (draft-ietf-mobileip-aaa-key-04.txt), I was wondering if you could help me
> understand the sections 6 and 7? The thing is that I don't see exactly what
> they can be used for. For example, is the MN-FA Key Request (section 6) sent
> in the MIP Registration Request in order to suggest a SPI between the MN and
> the FA? Then, I guess that the FA can suggest it to the AAAH in the AMR
> using the MIP-FA-MN-Preferred-SPI AVP, right? 

Correct, the MN can "suggest" a value, and the FA has the option to overwrite
that value. Sure, a possible collision could occur, but that's life :(

> I guess the FA can also
> suggest a SPI between the FA and the HA using the MIP-FA-HA-Preferred-SPI
> AVP, right? 

Right, if the FA likes the "suggested" value from the MN, then it would set
the same value in the AVP. Otherwise, it puts its own preferred value.

> However, if the MN sends a MN-HA Key Request (section 7)
> including a preferred SPI to be used between the MN and the HA, how can it
> be sent to the AAAH? It does not seem to exist any AVP for that in the
> Diameter Mobile-IP protocol. Can that subtype be used at all within the AAA
> infrastucture meaningfully?

hmmmm.... it doesn't appear to be used in Diameter. I am at a bit of a loss.
So, we can either create a new AVP, if we believe this is useful, or eliminate
the field from the Mobile IP extension.

> Also, note that in section 7, it is referred to the foreign agent instead of

yup, just caught that as I was reading over section 7.

PatC