Re: COPS-PR questions

[Keith McCloghrie <kzm@cisco.com>]

> * In draft "draft-ietf-rap-frameworkpib-02.txt", section 3.2 related to
> "Multiple PIB instances" 
> 
> >>Although many PIB instances may be configured on a device (the maximum
> number of these instances being determined by the device itself) only one of
> them can be active at any given time, the active one being selected by the
> PDP.  

An example of how this might be used is when the PDP has different sets
of policies for different times of the day, e.g., different policies for
9am-5pm versus at night.  In such a situation, the PDP would have to
download at 9am all the new policies that are different from at night,
and at 5pm, download all the nighttime policies that are to different
from the daytime policies, and it would have to do that every day.
Instead of that, the idea is for one "PIB instance" to contain the
9am-5pm policies, and another to contain the nighttime policies, such
that at 9am and at 5pm, the PDP needs only to change which "PIB instance"
is "active".

> The device in this sentence is it the one embedding the PEP, as I understand
> it ?

Yes.

> In this case, does it maintain the PIB instances locally (just like a
> device maintains MIBs for SNMP) or the PIB instances are they only
> maintained by the server ?

If the multiple sets of policies weren't stored locally, then there would
be no benefit, i.e, if they have to be downloaded at 9am and 5pm,
then the PDP might as well download them normally with DEC messages. 

> To justify the maintenance of PIBs locally, I'm thinking that these can be
> used by the LPDP for issuing local decisions, or by the PEP within the
> context of synchronization operations with a PDP, but I'm not pretty sure
> PIBs are really maintained locally as they are always represented residing
> at the policy server and these roles may be assumed by the configuration
> file of the device where the PEP resides.
 
Eh?

> >>To facilitate this selection, the Framework PIB supports an attribute to
> make a PIB instance the active one and, similarly, to report the active PIB
> instance to the PDP in a COPS request message. 
> Doesn't this sound a bit restrictive as a given PEP may support many
> Client-Types requiring different PIB instances to be active in the same time
> ?

The "active instance" is on a per-Subject Category (Client-Type) basis.

Keith.