Subject: RE: [AAA-WG]: Diameter encoding of RADIUS VSA AVPs

From: <[email-masked]>
Date: Wed, 26 May 2004 06:21:36 +0300

Hi Avi,

> Interoperability between other SDOs that is.

If it were so simple, I might have an easier time agreeing, but we
do know of several operators deploying 3GPP and 3GPP2 networks in
different places of the the world - they may have some need
for interoperability between these networks.  Also, different
SDOs (GSMA, IEEE) have interest in AAA standardization and the output
of these bodies may in fact be used by other SDOs.  

To put it differently, if the feature is worth standardizing, why
wouldn't interoperability (at some point) be a good thing?  
 
> At the SDOs vendors get together and agree on how to interoperate amognst
> themselves.  In the case of 3GPP2 they develop 3GPP2 specific VSAs.  In this
> case 3GPP2 can be viewed as super-vendor.

Taking this literally, I don't buy it.  The super-vendor is not selling
hardware/software/services, and if you're point is taken literally, I am
sure anti-trust regulators might have something to look into.
 
> The alternative is not to do this and take everything to the IETF.  So do
> you really think that the IETF has the cycles to address all the AAA
> requirements of all SDOs?  Cause I don't.

There's the rub, I agree.  I would say that the IETF doesn't have the 
cycles, processes nor will even to do this.  However, I believe that is
a discussion happening elsewhere, in one of the IETF process-oriented
working groups.

However, let's just say that I understand your point and agree we have to
live with it, however I am not sure that the IETF should give its blessing
to it.

John

---

From: Bernard Aboba <[email-masked]>
Date: Tue, 25 May 2004 20:56:06 -0700 (PDT)

> a discussion happening elsewhere, in one of the IETF process-oriented

Actually, I would say that the IETF is struggling with the extensibility
issue in general.  One potential model for AAA long term is the SNMP
extensibility model -- enabling SDOs to create their own MIBs, but
providing review via MIB Doctors and reserving protocol changes to the IETF.

Many of the issues that we have with SDO extensions derive from the lack
of a cleanly articulated data model in AAA.  For example, in SNMP there is
no difference in the data model between enterprise and standard MIBs.
This makes it possible to develop an enterprise MIB and bring it over into
the standards space without large scale changes.

But that is not the case with RADIUS -- VSAs have more variation and
flexibility than standard attributes do.  I believe that is inherently
problematic -- because it creates issues with bringing widely deployed
vendor-specific attributes into the standards space, as we have seen.

I would hope that over time we would be able to move more towards the SNMP
model in AAA -- where the data model is homogeneous between the enterprise
and standards space, where there are well articulated guidelines for
application design, and where there is a AAA Doctors group to assist IETF
WGs and SDOs in proper AAA application design.

That way, the IETF can focus on what it cares about most --
interoperability between implementations, while satisfying SDO needs for
AAA application review without having to spawn an endless stream of new WG
work items.

We're trying this approach now with IEEE 802.1, with David Harrington
serving as the MIB Doctor in residence.  The old approach of handling IEEE
802.1 MIBs in the IETF Bridge WG was no longer working, due to cutbacks in
standards budgets.  So we will see how this more "lightweight" model works
out for SNMP.

---

From: Jari Arkko <[email-masked]>
Date: Wed, 26 May 2004 12:33:10 +0300

> vendor-specific attributes into the standards space, as we have seen.

I believe this is the crux of the problem -- the bits are
different, and not just the official status of the extension.
If you add a difference in expressive power (in either
direction) and significant timeliness differences, this
brings even greater problems.

Where does that leave us? I think we need

   (a) Vendors and SDOs doing their own things in
       an easy manner, without having to bring everything
       to the IETF.

   (b) IETF specialist assistance in the above, where
       needed.

   (c) Migration towards the same expressive power and
       technical solutions whether its IETF standard,
       other SDO standard, or vendor specific solution.

   (d) Recognition that some of the solutions originally
       intended as an SDO-internal mechanism end up being
       a global interoperability issue. Example: replacement
       of FOOBAR SDO radio with wireless LANs, and expecting
       mobility or something like that to still work. Another
       example: developing a SDO specific multimedia network,
       and then later realizing the need for that network
       to interoperate with another SDO's multimedia network.

Anyway, we started this discussion from the rules regarding
RADIUS VSA usage in Diameter. Have we concluded what to
do for that? There was a suggestion to specify in RADEXT
what the universal and application specific VSA rules are,
but it isn't clear to me what attributes belong to which
part. Do we have suggested text?

--Jari