Object Identifiers

To keep track of all of the information stored in a MIB, each object is labeled with a unique tag called an object identifier . The object identifier is implemented as an internationally accepted, multi-part, hierarchical naming scheme that is governed by the Internet Engineering Task Force (IETF). This naming scheme allows developers and vendors to create new components and resources and to assign a globally unique object identifier for each new component or resource without duplicating any existing namespace.

SNMP management software applications use the object identifier to identify the managed objects on each agent. The management system sends a message that requests information about an object and identifies the object by the object identifier. The agent uses the object identifier to retrieve the appropriate information and sends the response back to the management system.

The object identifier itself is actually a sequence of labels that begins at the top of the hierarchy and ends with the object to which the object identifier is being assigned. As the example in Figure G.1 illustrates, iso.org.dod.internet.private.enterprise.lanmanager is the object name for LAN Manager and the object number is 1.3.6.1.4.1.77.

Figure G.1 MIB Namespace Hierarchy

At a specific level in the namespace hierarchy, the IETF grants to individual organizations the authority to create new MIBs under that organization. The private namespace assigned to Microsoft is 1.3.6.1.4.1.311 . Microsoft has the authority to create new MIB objects under this namespace and to assign names to them, such as the MIB object Microsoft IIS Service.