Subject: RE: [mobile-ip] Multiple flows with single NAI

From: "Glenn Morrow" <[email-masked]>
Date: Tue, 1 May 2001 11:19:29 -0500

Madhavi,

Are you thinking of the NAI as a:

subscription identifier
user identifier
Equipment identifier?

It seems to me that each device might have different home addresses. The key
can be a bit more complex than just an NAI into a database/directory used
for any purpose.

-----Original Message-----
From: Madhavi Subbarao [mailto:[email-masked]]
Sent: Monday, April 30, 2001 6:53 PM
To: [email-masked]
Cc: Madhavi W Subbarao
Subject: [mobile-ip] Multiple flows with single NAI

Hi All,

For viable deployment of MIP, it seems necessary to support single NAI
with multiple static IP flows.  For example, if a user opens a MIP
session on his laptop and then wants another MIP session on his phone,
he couldn't do that now with a single NAI .  Now when an HA receives
an RRQ with NAI and homeIP#2, but it already has a binding for NAI
and homeIP#1, the binding gets 'overwritten'.  Hence, only one MIP
flow can be supported per NAI.  Theoretically, we can say to use
multiple NAIs, but practically, it's not possible.  Many service providers
do not want to create multiple NAIs and user records for multiple
devices/applications or instances of the mobile user.

While it seems natural then to allow multiple static IPs for the same NAI 
(dynamic IPs also, but that needs another level of identification),
neither RFC2002 nor RFC2974 outline the behavior that should be
followed by the various entities.  The specs certainly do not preclude
the above, but clarity in behavior is needed.

We believe this is a simple, yet important issue for deployment and would
like feedback from the WG.

We've submitted a draft that addresses the above.
http://search.ietf.org/internet-drafts/draft-subbarao-mobileip-multipleip-00
.txt

Thanks,
Madhavi

---

From: Madhavi Subbarao <[email-masked]>
Date: Wed, 2 May 2001 16:56:18 -0400

Hi Glenn,

Sorry for the delayed response...

> Are you thinking of the NAI as a:

As a user identifier.  The NAI identifies the user, not the device.

> It seems to me that each device might have different home
> addresses. 

Yes, actually that's what we are saying.  Each device will have a
different home address...authentication is based on NAI (as is currently).
The HA authorizes the (NAI, IP address) combination.

> The key

I'm afraid I didn't catch your point.  Are you saying that you can't
still authenticate based on NAI?  Please elaborate...

Regards,
Madhavi

---

From: Michael Thomas <[email-masked]>
Date: Wed, 2 May 2001 14:04:15 -0700 (PDT)

> As a user identifier.  The NAI identifies the user, not the device.

   Hmm. I'm [email-masked], luser. I don't think an NAI
   expresses that meaning. I thought an NAI was an
   _interface_ identifier.

		Mike

---

From: Madhavi Subbarao <[email-masked]>
Date: Wed, 2 May 2001 17:56:44 -0400

>    Hmm. I'm [email-masked], luser. I don't think an NAI

Hmmm...I'm sure you didn't mean to say 'loser'...  Careful with your
typing...

>    expresses that meaning. I thought an NAI was an

From RFC 2486:

"...it is desirable to have a standardized method for identifying
users.  This document proposes syntax for the Network Access
Identifier (NAI), the userID submitted by the client during PPP
authentication..."

-Madhavi