Re: Augments clause and access of defined objects?

[Keith McCloghrie <[e-mail]>]

> In Regards to your letter <[e-mail]>us>:
> > > Since augments adds a conceptual row to a table under a new object name,
> > > am I correct that a get next sweep of the whole mib will traverse most of 
> > > the table (the non augmented part) twice?  Once for origional def and once
> > > with additional column(s)?
> > 
> > No.  The original table occurs once in the object tree.
>
> So, do the new augmented columns appear when traversing the origional
> table?
> 
> Is traversing the OID defined with the augments clause never done?
 
No, each table (the base conceptual table and the conceptual table 
augmentation) appears in its own part of the OID tree, as defined by 
the respective OBJECT-TYPE macros.  Thus, AUGMENTS has no effect on 
the operation of GetNext and GetBulk (apart from indirectly specifying 
how instances are identified in the conceptual table augmentation).

Rather, the AUGMENTS clause allows:

1. For a table which would otherwise need a DESCRIPTION clause saying:
"the conceptual rows in this table corresponds one-to-one with the
conceptual rows in fooTable, and each conceptual row in this table is 
identified by the same instance identifying values as its corresponding 
conceptual row in fooTable", the conceptual row of such a table can now 
say: AUGMENTS { fooEntry }.

2. For an agent which implements a single "method" routine for a table,
that agent can (if it so desires) implement a single method routine for 
the combined base conceptual table and conceptual table augmentation.

3. For a management station which retrieves whole rows of a table,
that mgt station can (if it so desires) retreive the whole rows of both 
the base conceptual row and the conceptual row augmentation.

Keith.