Subject: [mobile-ip] RE: [diameter] DIAMETER support for MIP question

From: "Kuntal Chowdhury" <[email-masked]>
Date: Tue, 2 Oct 2001 18:23:49 -0500

Pat,
Thanks for responding. I am still not clear on the following two issues in
"draft-ietf-aaa-diameter-mobileip-07":

1. Section 1.4 Page 12

AAAF in foreign network 1 will send back error code
"DIAMETER_ERROR_NO_FOREIGN_HA_SERVICE" to AAAH if foreign network 1 does not
wish to provide HA service when the MN has moved to foreign network 2.
However it is not mentioned when the AAAH receives such an error code from
AAAF what happens to the mobile IP registration request. 
I think some text is required to capture this exception case. Options before
AAAH is either send another HAR to AAAF in network 2 (only if AAAF had set
the "Foreign-Home-Agent-Available" flag in AMR), otherwise AAAH may assign a
HA in the home network or reject the mobile IP registration request. 

2. When MN requests for a HA allocation in the foreign network, and for some
reason AAAF does not set "Foreign-Home-Agent-Available" or AAAH denies the
request, how does the MN come to know that it did not get what it requested?

If it is immaterial for the MN's MIP client to know where the HA gets
allocated, why does it ask for it differently e.g. some MNs requesting with
0.0.0.0 and some others requesting with 255.255.255.255?

Regards,
Kuntal 

-----Original Message-----
From: Pat Calhoun [mailto:[email-masked]]
Sent: Tuesday, October 02, 2001 10:24 AM
To: Chowdhury, Kuntal [RICH2:2H18:EXCH]
Cc: [email-masked]; [email-masked];
[email-masked]; [email-masked]
Subject: Re: [diameter] DIAMETER support for MIP question

hmmm... first off, version 2 is quite old, and 7 should be used (or even
better
the 08 alpha released last week).

In the later versions, the AAAF sets a bit if it is willing to provide HA
services
in the foreign network. Further, the AAAH has the option to choose whether
it is
willing to let the mobile use this service. If so, it forwards the HAR to
the
foreign network's AAAF, otherwise it sends the HAR to a local HA.

The zero HA address is a request to have a home agent dynamically assigned
to the
mobile.

hope this helps,

PatC
On Mon, Oct 01, 2001 at 02:15:31PM -0500, Kuntal Chowdhury wrote:
> Pat/Charlie,
> I am curious to know the implication on a mobile node when it sends
0.0.0.0
> in the HA address field in MIP registration request for HA assignment in
the
> local network but the HA gets assigned in the home network. In section 4.2
> in "draft-ietf-aaa-diameter-mobileip-02", there is an error code
> "DIAMETER_ERROR_NO_FOREIGN_HA_SERVICE 5007" which AAAF sends back to AAAH
to
> inform that it cannot assign a HA in the local network. In this case, does
> the AAAH assign a HA in the home network? Does the mobile node get any
> indication of this event? 
> 
> Regards,
> Kuntal

---

From: Pat Calhoun <[email-masked]>
Date: Wed, 3 Oct 2001 09:23:30 -0700

> HA in the home network or reject the mobile IP registration request. 

The text that follows is at the end of section 1.4 and I believe it does
cover this error:

"
   If the old Foreign Network does not permit the use of its Home Agent
   when the Mobile Node moves to a new foreign network, the AAAH or AAAF
   MUST return an AMA with the Result-Code AVP set to
   DIAMETER_ERROR_HA_NOT_AVAILABLE. Upon receipt of this error, the
   Foreign Agent MUST issue a Mobile IP Registration Reply to the Mobile
   Node with an appropriate error. The Mobile Node MAY attempt to
   request that a new Home Agent and Address be allocated. When the AAAH
   transmits such an error, it MUST issue a Diameter Abort-Session-
   Request message to the AAAF overseeing the Home Agent to enable it to
   release any resources."

Is this not sufficient?

> request, how does the MN come to know that it did not get what it requested?

It would receive the Registration Reply with the proper error code. There are
a variety of error codes defined in RFC2002, but perhaps a more specific error
code could be introduced? If so, where should it be specified?

> 0.0.0.0 and some others requesting with 255.255.255.255?

corporate customers would most likely want an HA in their corporate networks.
Normal Internet users don't care where the HA resides.

PatC