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Re: snmpconf Pointers from Policy MIB -> implementation-specificMIB



on 07/06/2000 2:22 PM, Andrew Smith at ah_smith@pacbell.net wrote:

> David,
> 
> I'm a bit worried about the scalability of this approach, but maybe I'm
> misunderstanding something about the proposal: are you saying that the
> "manager" would create all the rows in this table, one row for every low-level
> object instance that is affected by a high-level policy? That could be
> literally thousands of entries per-device for a single high-level rule.
> Alternatively, if the device creates them automagically, wouldn't some more
> interesting indexing be better, rather than having to plough through a flat
> list? (It's not clear from your MIB-fragment which you intended).
> 

Andrew, David P. is on holiday so he may not be able to respond quickly. It
is definitely not the case that there would be a row in the table David
described for every object instance. The pointer that is referred to in the
proposed addition to the Policy MIB Module is a row pointer to the mechanism
and implementation specific MIB Modules. In the case of the DiffServ MIB
Module that David and Harrie are working on.
 
> But I'm still not clear on all the downsides to strategy (1). To me, if you
> (the manager) know which high-level rules map to which low-level MIBs/table
> then there is no problem to go to that MIB (or to a MIB that AUGMENTs tables
> in that low-level MIB) to debug it. You're going to have to know about the
> different indexing requirements of the low-level tables anyhow, in order to
> make sense of the results so I'm not convinced that the centralised approach
> can be used to make any sort of useful generic "policy debugger" tool.
> 
I am not sure that this has been presented with enough background to be
clear yet. I believe what was intended is:
                   
Policy Module
    |
    |
PolicyTable           Proposed Table of 2 objects AUGMENTS Policy Table
    |
    |-PolicyEntry.1-->pmPolicyMechanismIndex,pmPolicyMechanismPointer
    |-PolicyEntry.2-->pmPolicyMechanismIndex,pmPolicyMechanismPointer

In the case of the work in David and Harries module, the
pmPolicyMechanismPointer would be a RowPointer to an entry in the
diffPolicyPHBTable. It contains a diffPolicyPHBId Object that is the index
to the table.
        
This table would allow pointing to multiple mechanism and implementation
specific tables for a single policy. It would also allow an entry in the
diffPolicyPHBTable to be referenced by many policies.

/jon