Subject: Re: need for COPS - was "Suggested new charter ..."

From: "Raju Rajan" <[email-masked]>
Date: Tue, 1 Jun 1999 10:50:35 -0400

Hi,

The interim policy meeting was very useful in clarifying several questions
that I had. Let me put out some of what I learned in the hope of clarifying
things for others with similar questions. (The official minutes will come
out whenever John/Ed put them out; if what I say conflicts with the minutes,
be sure I'm right :) )

1. There seemed to be considerable support for the position that policy
should be declarative and not procedural. This will be reflected in the
framework and the core documents.

2. The PIBs were not included as a work item on the charter, though it was
recognized that some means of recording PEP capabilities, policy errors and
policy usage information was vital to the correct operation of policy
servers/repositories/devices. It was thought that the PFWG had too much on
its plate already, and it would be better to deliver something and then
argue for the importance of more delivarables.

3. There seem to be two usages of the notion of PIB. One is an inclusive
notion that says that we need to store certain PEP related information
somewhere -- in the PEP, directories or elsewhere -- accessible through
multiple means -- LDAP, COPS, SNMP. I strongly support this inclusive PIB;
my personal interest is (primarily)  in using MIB formats for PIBs and
letting them be retrievable through SNMP. But I see the importance of other
protocols/information formats as well.
  The other exclusive  notion of PIBs is tied intimately to a data format
that is "slightly modified MIBs" retrievable through COPS alone. I believe
that we should not embark on such an effort. (Not that we are any danger of
doing so.)

Thanks,

raju rajan

----- Original Message -----
From: John Schnizlein <[email-masked]>
To: Keith McCloghrie <[email-masked]>; <[email-masked]>
Cc: <[email-masked]>
Sent: Thursday, May 27, 1999 9:26 AM
Subject: need for COPS - was "Suggested new charter ..."

> At 06:56 PM 5/26/99 -0700, Keith McCloghrie wrote:
> > in reply to Raju Rajan's:
> >> 3. If the use of PIBs is to put in hooks through the policy working
> >> group so that COPS may be the carrier of this information at a
> >> later date, I say great! But let's say so right up front, so that
> >> those of us interested in design/implementation can take a closer
> >> look at how it all fits together, what works, what doesn't and build
> >> it right. If PIBs are to be an essential component of the architecture,
> >> then let's not pretend in various architectural drawings that an
> >> LDAP-only router solution is even supported.
> >> We are saying that QoS policy is impossible without COPS.
> >> (I have no problem with such an architecture, and to the best of
> >> my knowledge, neither does AT&T :)
> >
> >I've not heard people say "QoS policy is impossible without COPS".
> >Rather, I think we've said that it's essential to allow the PEP and PDP
> >to be separated (to introduce hierarchy, and therefore scaleability),
> >and that COPS is being specified as a standard protocol for PEP-PDP
> >communication.
>
> We should recall the point of view that directories were designed
> around hierarchy, so that hierarchy was introduced with LDAP,
> although LDAP relaxes the obsession with hierarchy in X.500.
>
> A more central question is if the hierarchy of the directory
> (more attention needed on the containment issues Lee raised in MN)
> is sufficient. And the question of how dynamic policy propagation is
> needs to be resolved. Before MN, drafts differed in whether policy
> should be distributed through an event notification mechanism.
> Everyone seemed to agree signalling between nodes is necessary.
>
> It seems to me that policy can be static enough for the propagation
> speed of directory replication (which provides both reliability and
> distribution) if "policy" is defined as those rules the administrator
> wants enforced across all the state transitions in the network.
> This returns us to the question of "What is policy?" in a way that
> relates directly to the architecture, assuming the hierarchy in the
> directory can be used effectively to represent the semantics of policy.
>
> If we don't get consensus on the question if policy should be declarative
> or procedural, it is not clear we can get in on other questions.
>
> John
>