Redundant objects

["Dave Thaler" <dthaler@windows.microsoft.com>]

I'm wondering if there is any "official" policy on
redundant objects.  I don't see any mention in the
guidelines for MIB reviewers.  I know there are 
published books from various folks that mention 
this issue, but so far I haven't found if there's
some IETF doc that does.

One example would be objects which are trivially
derivable from other objects in the same MIBs, such
as "PacketsAccepted", "PacketsDropped", and their
sum "PacketsReceived".  While this is generally
discouraged, I couldn't find text so far that says
this.  Any pointers?

Another example would be objects which are trivially
derivable from objects in a different MIB.

The example of the day comes from the MPLS TELINK
MIB, which one of the authors says regarding an
IP address object:
> You are right, it is the latter. The IP address 
> is the IP address of the teLink interface. It is 
> redundant with ipAddrTable, but we would like not
> to have to rely on the presence of ipAddrTable 
> to get access to this information.

I'm interested in others' thoughts on under what
circumstances redundant objects are acceptable
(e.g., maybe if the conformance requirements
are different, or if the derivation is non-trivial
and significantly easier for the agent to do than
the management station), and whether this topic 
should be mentioned in the guidelines doc.

-Dave Thaler