Subject: RE: DSL Scenario

From: "Patil Basavaraj (NET/Dallas)" <[email-masked]>
Date: Thu, 3 Jan 2002 14:33:26 -0600

David,

In your examples of the DSL line terminating at a business or shared
by multiple family members, I do not believe PANA will be able to solve
the problem of authenticating every user in the household or
authenticate 
each user in a business.

PANA aims to authenticate the business account or the household account.
So the user in each of these instances is the business itself or the
household
account (maybe the phone number in this instance or a userid associated
with
the account). 

The fact that there may be multiple users attached to the DSL connection
is
outside the scope of PANA. Also the ability to differentiate services
provided
to the various users behind the DSL connections is outside the scope. 

What is in the scope is the ability to provide "IP srevice" as Erik put
it in
his earlier email. In order to do that the user has to provide
credentials and
authentication information using a messaging protocol which will be
defined
by this WG.

Access control is a derivative of initial authentication. How this is
accomplished
when you have for eg a /64 address assigned to the user is also outside
the
scope of the WG.

-Basavaraj

---

From: Reinaldo Penno <[email-masked]>
Date: Fri, 4 Jan 2002 10:42:22 -0800 (PST)

Hello,

This goes back to the discussion on the meeting if
PANA is directed to devices or users (real users). 

It seems that PANA is going to fit properly in a
mobile world where you carry your device around and
usually do not share it with anyone, but will have a
hard time in broadband access if the model assume is
1:1 (one device, one user).

The DSL scenario described is very true today and
applies to other access methods like cable, Ethernet,
etc. In one household people have different needs. You
can have for instance content filtering to the kids
and not to the parents, and this is tied to the
authentication/authorization. Same goes for other
services.

Although PANA is directed to devices (on behalf of
users), we should not assume that a device is owned by
a single person. Since the PANA protocol is used for
conveying information about the user, and not the
device, it doesn't make sense to make a protocol tied
to the device since different people using the same
device can have very distinct rights and services.

regards,

Reinaldo Penno

--- "Patil Basavaraj (NET/Dallas)"
> when you have for eg a /64 address assigned to the

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---

From: Yoshihiro Ohba <[email-masked]>
Date: Fri, 4 Jan 2002 15:50:48 -0500

> 1:1 (one device, one user).

If my understanding is correct, the most flexible PANA model assumes
m:1 (one or more devices, one user at the same time), but does not
assume 1:m (one device, one or more users at the same time). The
reason for not assuming 1:m was discussed about six month ago .  See
the following (BURP was the old name for PANA) which can be also find
in http://www.toshiba.com/tari/issues.txt.

--------------------------------------------------------------------
Issue #7: Is it possible to use BURP for sharing a single IP address 
          but separating accounts among multiple users?

It is difficult for the following reason.  To support such a
capability, partitioning TCP/UDP source port numbers based on user
identity would be necessary.  However, this would impose significant
modification in existing OS and application software to support that,
which seems unacceptable.  So in the current requirement this should
be avoided unless we see strong arguments or compelling need.
--------------------------------------------------------------------

> authentication/authorization. Same goes for other

If the above mentioned scenario is possible by using the m:1 model, 
we can add the scenario to the draft.

> device can have very distinct rights and services.

It depends on the meaning of "different people using the same
device".  If it means that different people using the same
device *at the same time*, it is diffucult for PANA to support 
the model since it is 1:m model.

On the other hand, it would be easier for multiple users to use the
same device at different times, which is m:1 model instead of 1:m, and
PANA should work with those models.

Yoshihiro Ohba

---

From: Yoshihiro Ohba <[email-masked]>
Date: Fri, 4 Jan 2002 16:05:38 -0500

> assume 1:m (one device, one or more users at the same time). The

Correction: 1:m (one device, multiple users at the same time)

Yoshihiro Ohba

---

From: David Spence <[email-masked]>
Date: Tue, 08 Jan 2002 14:53:29 -0500

However, even the m:1 model does not mandate a single authentication and
authorization for an entire prefix as is proposed for the DSL scenario.

---

From: Yoshihiro Ohba <[email-masked]>
Date: Tue, 8 Jan 2002 15:15:28 -0500

> authorization for an entire prefix as is proposed for the DSL scenario.

Could you elaborate on this?

Yoshihiro Ohba

> > in http://www.toshiba.com/tari/issues.txt.
Content-Description: Card for David Spence

---

From: David Spence <[email-masked]>
Date: Tue, 08 Jan 2002 16:10:13 -0500

Yoshihiro Ohba wrote:
>...

The elaboration would be my original posting that started this thread which
I include below:

> In section 3.1.3.3 (Interface Sharing) of
> draft-ohba-pana-usage-scenarios-00.txt, the authors state:
> 
>      "In terms of both access control overhead and AAA signaling overhead, 
>      it would be desirable to perform access control per prefix rather than
>      per child device."
> 
> The scenario goes on to show how a /64 prefix could be assigned to the
> "user" and shared among the user's devices.
> 
> While I would not want to rule out such a scenario, I do not necessarily
> agree that it would be desirable to perform access control per prefix rather
> than per child device.  I could imagine that there are really multiple users
> behind the prefix that have different authorizations and thus require
> different identifiers and separate authentications.
> 
> Suppose, for example, that the DSL line terminates at a residential
> subscriber.  The service is shared by multiple family members.  Some family
> members are authorized to use certain premium services for which the cost or
> content is considered inappropriate for other family members.  Or the DLS
> line may terminate at a small business.  There may be a requirement to track
> usage by individual user (the third A).
> 
> Therefore, locating the PANA client on the gateway device should be one
> option.  But the solution should not preclude locating the PANA client on
> the individual user devices.  The implication here is that the prefix
> assignment should be done outside of PANA.

---

From: Yoshihiro Ohba <[email-masked]>
Date: Tue, 8 Jan 2002 17:19:38 -0500

Now I understand your point, and you are right.

As you pointed out, per-prefix access control is not always necessary.
Instead, access control can also be performed per-child device like
IPv4.  Both fits the m:1 model and PANA should work with both cases.

I'll make it clear in the next version of the usage scenario document.

Thanks,
Yoshihiro Ohba