Subject: Re: PQIM draft issues

From: Mahadevan Iyer <[email-masked]>
Date: Fri, 27 Oct 2000 03:02:05 -0700 (PDT)

> >>(16) It is important to keep in mind that there
> will be more forwarding 
> >>actions beyond the QoS ones specified here. For
> example, NAT, Tunneling, 
> >>and stateful firewalling services are all
> functions that are in the 
> >>packet processing engine and that occur in the
> path between the ingress 
> >>and egress ports of a router. Therefore, it is
> important to be able to 
> >>define a sequence of actions with various decision
> points along the path. 
> >>It may well be that this model supports these more
> complex scenarios, but 
> >>there was not enough detail in the section for me
> to determine with any 
> >>level of confidence that this model could be
> sufficiently extended.

I had tried to raise a related issue at the last IETF
meeting but am still looking for a home for an
information model that cuts across these functions.
Each of these functions (firewall, bandwidth
management, NAT, IPSEC etc) tend to use the same
building blocks and are often clubbed together by
choice or by necessity. 

In such cases there is a need for an information model
that had a common policy condition clause, with
several action clauses related to each supported
function.

Further more instead of redefining the QoS actions
here as well as the RAP WG, or IPSEC policies in the
IPSEC WG, it would make more sense to ask them to plug
in their actions into a common policy framework. 

> >
> >We've been looking into these issues. I'm deferring
> this to Ron as the 
> >primary action modeler, but I think your point is
> to be seriously 
> >considered here.
> >

I will stop here and point you to a draft sent out
earlier for those interested in reading further. 

http://www.ietf.org/internet-drafts/draft-iyer-policy-ipvpn-info-model-00.txt

I expect to put out a new revision soon, but I would
like to draw your attention to the general purpose of
the draft.

Thanks

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---

From: Yoram Ramberg <[email-masked]>
Date: Sun, 29 Oct 2000 10:09:48 -0500

What you're saying is, in fact, the motivation behind drafting the core 
policy information model (PCIM) in the first place 
(draft-ietf-policy-core-info-model-08.txt, moving quickly toward an RFC status)
Does this draft do the job of establishing a sufficient info model to 
accomplish the goal set to it? You may argue that it doesn't and I grant 
you this would start (continue?) a lively and heated discussion. However, I 
suggest to you that this is the (large part of the) WG charter and this is 
the document that should be discussed.
Some have opined that a certain portion of the QPIM specification 
(draft-ietf-policy-qos-info-model-01.txt, a -02 revision should be 
available very soon) actually belongs in PCIM due to its generic nature. 
For example, several abstract/base action classes that were defined in QPIM 
can be used by policy systems in areas such as traffic engineering, 
security and possibly ipvpn as well. Another, more general example is the 
introduction of variables/values/constants mechanisms in QPIM that can 
certainly be thought of as general (maybe even beyond Policy...).
Surely your argument has merits and I believe Walter (whom you quote in 
your letter) would agree with you.

Now, I've taken a quick look at your ipvpn policy draft and experienced 
very little difficulty in identifying duplication of efforts due to the 
above shortcomings of the existing models. For example, you had to define 
IP address type (v4, v6) and variables (although you don't call them 
variables...).

I also must tell you that the use of qpPHBset in the ShapingAction class 
must be revisited due to changes in the latest draft (-02) of QPIM. That's 
unfortunate but unavoidable... There are other such examples. In fact, you 
might wish to take a look at the new QPIM draft and see if your action 
model can be better aligned with QPIM.

Also - in the last IETF (Pittsburgh) two new drafts were presented to model 
TE policy. Should you consider merging the efforts there? Should you absorb 
TE policy into ipvpn policy? Note I'm not proposing, only asking. You're 
the experts and I'd like to here your opinions.

Thanx,
*Yoram