Subject: RE: [AAA-WG]: Mobile IP Extension

From: "Haseeb Akhtar" <[email-masked]>
Date: Fri, 9 Mar 2001 12:33:07 -0600

All,
 
Yes, I do realize that implementing multiple functions in one message 
may increase complexity. However, what we gain is the reduction in
round trip delay - specially for the case when the HA has to be allocated
in the visited network.
 
As far as the servers being stateful, well, they already are. That's why
Diameter
has the concept of Session Termination (section 11.7 of the Base).
 
Although AMR deals with user authentication (MN-AAA), the HAR too carries
Mobile IP user authentication information (MN-HA, FA-HA, MN-HA etc.).  That
is, HAR does not ONLY deal with HA assignment.
 
I did not quite understand Pat's comment as to why this approach with make
it
difficult to have single code base that supports both client and server
side.
 
Regards,
 
Haseeb

Hassib, 
 
How are you doing? Having AMR and AMR do different functions based on the
session state is unusual. The implementation and maintenance of this in the
server will not be easy. Also, this mandates servers to be stateful. I agree
with Pat's solution so far. 
 
John Alayari.  

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Tony Johansson
Sent: Thursday, March 08, 2001 3:22 PM
To: Haseeb Akhtar
Cc: 'pcalhoun'; aaa-wg; diameter
Subject: Re: [AAA-WG]: Mobile IP Extension

Hi Haseeb, 

I disagree with you. An AMR and an HAR are two different things. The AMR
deals with user authentication and the HAR deals with HA assignment. We have
been discussing this during the interop test even in San Jose and I strongly
believe that the most logic way of doing this is as Pat describes it below. 

BR, 

/Tony 

hmmmm.... I recall having this discussion, and I am quite sure that my
response

will be the same.

I really do not care much for messages that have to be treated completely

differently, based on whether the receiver is a home server or a home agent.

Your proposal makes it REALLY hard to have a single code base, that supports

both client and server side (NAS/FA and AAAH).

Anyone else?

PatC

---

From: Pat Calhoun <[email-masked]>
Date: Fri, 9 Mar 2001 17:31:45 -0800 (PST)

> round trip delay - specially for the case when the HA has to be allocated

well, the draft, as it stands already has this, but at the expense of message
abuse (meaning the intent of a message is not clear by its command code,
guessing is involved) and complexity.

> has the concept of Session Termination (section 11.7 of the Base).

not necessarily. The protocol allows for servers to be stateful, but my server
is in fact quite stateless. People at connectathon were in fact surprised at
how little state my server has. This, btw, was intentional in order to
validate whether such an implementation is at all possible.

I would hate to disallow such implementations...

> is, HAR does not ONLY deal with HA assignment.

It is used to hand a Registration request to the HA. That's what the HAR is
all about. There is no authentication/authorization of the user, since this is
done in the AAAH (as a result of the reception of the AMR).

> difficult to have single code base that supports both client and server

Sorry, I was a little vague here. My point was close to Tony's.

I know that when my Diameter code receives an AMR, and the Destination-Realm
is set to my own realm, I can handle that message, authenticate/authorize the
user, generate keys if necessary, and then hunt for a home agent. 

My code also knows that when an HAR is received, and the Destination-FQDN is
set to the local hostname, it is to be handed off to the Mobile Agent process.

If both messages were AMRs, I am not sure how I would *know* whether to
authenticate the user, or hand the RegReq to the mobility agent.

Hope that makes more sense,

PatC