Information that is exchanged between management systems is modeled in
terms of managed objects. Managed objects are views of resources; these
resources may exist independently of management concerns, or may exist to
support the management of other resources. A managed object may represent,
for example, a modem, a log, or a circuit.
In order to allow effective definition of a growing set of managed objects, we
use object-oriented design principles. Object-oriented design is
characterized by the definition of objects, where an object is an abstraction
of a physical or logical thing.
There is not necessarily a one-to-one mapping between managed objects and
real resources. A managed object may represent one or more resources.
These resources can be managed
elements or parts of the management solution. Likewise, a resource may be
represented by a zero, one, or more managed objects. If a
resource is not represented by a managed object, it cannot be managed across
the interoperable interface.
A managed object may provide an abstract view of resources that are
represented by other managed object(s).
A managed object is defined by:
A managed object class defines a ;SPM_quot;type;SPM_quot; of managed object, and a member of a
managed object class is called a managed object instance. All managed object
instances in the same class have the same attributes, operations, behavior
and notifications. The term ;SPM_quot;managed object;SPM_quot; is used to mean ;SPM_quot;managed object
instance;SPM_quot;, if this meaning is clear from context.
Although managed object classes may be defined for anything which needs to
be managed, it is useful to give some examples of managed object classes to
help in understanding this wide variety. These examples show that managed
object classes can be defined for physical and logical components, or to
represent some other aspect of management.
A facet of object-oriented design is that of encapsulation. Encapsulation is
a form of information hiding, in that all implementation details, internal
structures, etc. are known only to the implementation of the object. For any
object, only the properties defined for it are visible. That is, the internal
operation of a managed object (or its mapping to a real resource) is not
visible at the object boundary unless attributes, operations, behavior or
notifications are defined to expose this information. How operations are
enforcement of any appropriate consistency constraints are determined by the
definition of the managed object class.
the attributes visible at its boundary,
the management operations which may be applied to it,
the behavior exhibited by it in response to management operations,
the notifications emitted by the object.