Subject: [Dime] one Diameter application or two for the Rr reference point?

From: Fortune HUANG <[email-masked]>
Date: Thu, 21 May 2009 11:13:23 +0800

Dear all,
 
In ETSI TISPAN RACS architecture, we have a Diameter based Rr reference
point between two x-RACFs.
The Rr reference point supports two models:
1) Request Model: where one x-RACF instance solicits the admission decision
and resource reservation (e.g. initial reservation, modification, release)
from another x-RACF instance that is also responsible for the admission
control of those resources within that network segment. The request model
can only operate with the per-request level, and doesn't require an explicit
pre-delegation process of responsabilities.
2) Delegated model: where one x-RACF instance explicitly delegates
responsibility for a bulk of resources to another x-RACF instance, which
thereby becomes responsible for the admission control for those resources
without the need to further involve the other instance.
 
Each pair of x-RACFs can only have the Rr reference point supporting either
the Request Model or the Delegated model but not both.
For the Request Model, the Rr reference point should be
SESSION_STATE_MAINTAINED, but for the Delegated model, the Rr reference
point should be SESSION_STATE_NOT_MAINTAINED. And the messages and
parameters will be very different between the two models.
 
My question is: should we have only one Diameter application supporting both
models or two different Diameter applications for each model of the Rr
reference point?
 
I would be very grateful if someone here can give me some guidance on this
question.
 
BTW, I also had a look at draft-ietf-dime-app-design-guide-08, but couldn't
find the answer. Maybe we could abstract some guideline on how to solve this
kind of questions and add them to draft-ietf-dime-app-design-guide after
this question is well solved.

Best Regards,
Fortune