Re: rap-sppi-02 EXTENDS clause instance mapping??

[Keith McCloghrie <kzm@cisco.com>]

> Diana> I've look closely at section 8.8 as well as the Framework PIB
> Diana> and COPS-PR documents.  It must be a case of "seeing but not
> Diana> understanding!"
> 
> Diana> So does the PDP specify an EXTENDs policy using two bindings?

Yes.

> Diana> The first binding installs the base row policy instance and the
> Diana> second binding installs the EXTEND's policy instance.

This is the text which says that:

                                             However, an instance of a
   sparsely augmenting PRC need not exist when the corresponding instance
   of the PRC that it sparsely augments exists.  Thus, an instance of a
   sparsely augmenting PRC can be installed at the same time as, or
   subsequent to the installation of, and can be removed prior to the
   removal of, the corresponding instance of the PRC that it sparsely
   augments.  So, instances of a sparsely augmenting PRC must be installed
   explicitly, but are removed either implicitly (via removal of the
   augmented PRI) or explicitly.

> Diana> The PRID
> Diana> of the second binding is constructed using the PRC OID of the
> Diana> EXTENDs table object and the instance ID of the base instance
> Diana> as the last sub-identifier.

Yes, and this is the text tha says that:

                              Instances of a sparsely augmenting PRC are
   identified according to the PIB-INDEX clause of the row definition named
   in the sparsely augmenting PRC's EXTENDS clause.

> Diana> Is it true that a base row instance is not reused by multiple
> Diana> EXTENDS instances?
> 
> I don't think this statement is generally true. You can have multiple
> AUGMENTS on a single base row (at least in the SMIv2) and I would
> expect that you can have multiple EXTENDS on a single base row. Note
> that this does not imply that multiple EXTENDS on a single base row
> always make semantically sense.
 
Correct.

Keith.