MIB Tree Structure
All the MOs in a network compose the tree structure of the MIB. The leaf nodes of the tree are managed objects. An MO is identified by the set of nodes along the path from the root to the leaf node. Such a path is called object identifier (OID).
Figure 1 shows the MIB tree structure.
An OID consists of positive integers and zero, and it is used to uniquely identify an MO in the MIB. The SMI ensures that each OID is unique within a MIB.
Once the MIB file is released, OIDs are bound to the MOs. The binding cannot be modified. The MOs in the MIB cannot be deleted, but can be set to obsolete indicating that the MO is not used.
In the tree structure shown in Figure 1, the MO mgmt is represented by { iso(1) org(3) dod(6) internet(1) mgmt(2) } or 1.3.6.1.2 that is called OID.
The NMS refers to an MO by specifying the OID.