| Description | This OBJECT IDENTIFIER value identifies a table in which all
elements of this type will be found. Every row in the
referenced table will be treated as an element for the
period of time that it remains in the table. The agent will
then execute policy conditions and actions as appropriate on
each of these elements.
This object identifier value is specified down to the 'entry'
component (e.g., ifEntry) of the identifier.
The index of each discovered row will be passed to each
invocation of the policy condition and policy action.
The actual mechanism by which instances are discovered is
implementation dependent. Periodic walks of the table to
discover the rows in the table is one such mechanism. This
mechanism has the advantage that it can be performed by an
agent with no knowledge of the names, syntax, or semantics
of the MIB objects in the table. This mechanism also serves as
the reference design. Other implementation-dependent
mechanisms may be implemented that are more efficient (perhaps
because they are hard coded) or that don't require polling.
These mechanisms must discover the same elements as would the
table-walking reference design.
This object can contain a OBJECT IDENTIFIER, '0.0'.
'0.0' represents the single instance of the system
itself and provides an execution context for policies to
operate on the 'system element' and on MIB objects
modeled as scalars. For example, '0.0' gives an execution
context for policy-based selection of the operating system
code version (likely modeled as a scalar MIB object). The
element type '0.0' always exists; as a consequence, no actual
discovery will take place, and the pmElementTypeRegMaxLatency
object will have no effect for the '0.0' element
type. However, if the '0.0' element type is not registered in
the table, policies will not be executed on the '0.0' element.
When a policy is invoked on behalf of a '0.0' entry in this
table, the element name will be '0.0', and there is no index
of 'this element' (in other words, it has zero length).
As this object is used in the index for the
pmElementTypeRegTable, users of this table should be careful
not to create entries that would result in instance names with
more than 128 sub-identifiers. |