Re: COPS usage

[Nguyen Thi Mai Trang <maitrangqos@yahoo.com>]

Hi Tina and all,

Thanks alot for your answer. Permit me to have two other questions.

3. Can a PDP of a client-type be a PEP of another client-type? For exemple, in
the same machine of  the COPS-PR PDP, I implement a SLA-PEP who occupies the SLA
establishment with another domain.

4. In the same client-type, can a PDP be a PEP of another PDP? For example, in
the same machine of the SLA-PDP who manages all SLAs of  domain A, I implement a
SLA-PEP who occupies the SLA establishment with domain B.

I poste these four questions because of the following context:  (see the exemple

in question 4)  when a client of  domain A requests a SLS to the SLA-PDP of
domain A, if this is an intra-domain SLS request, the SLA-PDP may accept this
request and make some changes in the COPS-PR Policy Repository. If this is an
inter-domain SLS request, the SLA-PDP does not reply yet, it transfers this
request to the SLA-PEP who occupies the SLA establishment with domain B. When
the request is accepted by the other domain, it may accept this request and make
some changes in the COPS-PR Policy Repository of domain A.

My friend says that "If you implement three entities (COPS-PR PDP of domain A,
SLA-PDP of domain A, SLA-PEP for SLA establishment with domain B) in the same
machine, it conflicts with the Policy Based Management Framework and
Architecture. Firstly, a PDP can not a be PEP. Secondly, all a PDP does is send
the DEC to the client, not other things (e.g. make some changes in one Policy
Repository). Thirdly, a COPS-PDP can not make some changes in the Policy
Repository because they are not in the same abstraction level".

I say that "It doesn't conflict with the architecture and the framework.
Firstly, why can not a PDP be a PEP when they are logically two separate
entities? Secondly, I don't find out in the RFCs the convention that the PDP can

not make other things than sending the DEC to its client. Thirdly, "a PDP makes
some changes in its Policy Repository" may conflict with the architecture BUT "a

PDP makes some changes in the Policy Repositoy of another PDP" does not conflict
with the architecture. How it can make some change in the other Policy
Repository is the implementation problem "

We can not arrive the conclusion:-( Excuse-me for a long message but I only hope

for getting the answer in the mailing list of RAP WG who defines the Policy
Based Management Framework and Architecture.

Thank you very much in advance.
Mai Trang

"Iliff, Tina" wrote:

> Mai Trang,
>
> Here is one answer or recommendation to your questions.
> 1. I would recommend using COPS usage for RSVP.
> 2. No, it does not conflict.  In fact, you can consider this as an example
> of an "external event" which is mentioned in the COPS RFCs.
> Tina Iliff
>
>  -----Original Message-----
> From:   Nguyen Thi Mai Trang [mailto:maitrangqos@yahoo.com]
> Sent:   Monday, June 11, 2001 11:34 AM
> To:     rap@ops.ietf.org
> Subject:        COPS usage
>
> Hi all,
>
> I have a question about the COPS protocol usage.
>
> In the normal operation of COPS-PR, the network administrator will creat the
> policies and stock them in the COPS-PR Policy Repository. The COPS-PR PDP
> connects to the COPS-PR Policy Repository to retrieve the policy and
> configure
> its PEP.
>
> I would like to make a SLA server who manages all SLAs of the domain.
> Instead of
> creating all the policies for the COPS-PR Policy Repository, the
> administrator
> will creat the policies for the SLA server and stock them in the SLA Policy
> Repository. The SLA server connects to the SLA Policy Repository to retrieve
> the
> policy. The SLA policy helps the SLA server decide to accept or refuse a SLS
> requested by his client. Once the SLA server accept a SLS (i.e., the SLA is
> established), it will make some changes or generate some new rules in the
> Policy
> Repository of the COPS-PR Policy Repository so that the COPS-PR PDP can
> properly
> configure its PEPs.
>
> My questions :
> 1. Am I permitted to use the COPS protocol for the communication between the
> SLA
> client and the SLA server ? call the SLA server the PDP and I call the SLA
> client
> the PEP ?
> 2. If the answer of question 1 is "yes", is the fact that the SLA PDP make
> some
> changes in the Policy Repository of COPS-PR PDP conflict with the Policy
> Based
> Management Framework and Architecture ?
>
> Thank you very much.
> Mai Trang

--
----------------------------------------------------
Nguyen Thi Mai Trang
Ecole Nationale Superieure des Telecommunications
Dept. INFRES - Bur. C234-4
46 Rue Barrault - 75013 Paris
Tel: 01 45 81 72 61 - Fax : 01 45 81 31 19
email : trnguyen@enst.fr