Understanding the network.pdf - Back to Home

The MIB-2 and RMON-MIB modules are perhaps the most recognizable and widely
implemented. Almost every Internet standards-based technology has a standard
MIB module. MIB modules exist for 802.3 Ethernet, ATM, BGP, DNS, SONET, OSPF,
and Frame Relay, to name just a few. Devices that support SNMP and utilize these
technologies will generally implement support for some or all of the standard's
defined MIB module groups.
Experimental MIB modules are essentially "MIBs in progress." During the
standards-based MIB development process, MIBs are assigned temporary MIB
identifiers for testing. Once the MIB becomes a standard, it is assigned a unique,
standard MIB identifier.
Enterprise MIB modules are developed for specific devices by manufacturers. These
MIB modules permit manufacturers to develop management capabilities for their
products' specific features. A device-specific MIB will often implement objects and
object-groups from standard MIB modules. Although all SNMP supported devices
will support standard MIB modules to some extent, it is the vendor-specific MIB
module that provides the additional control and management capabilities that are
often needed to manage the device effectively. When using a management system,
you typically need to install your equipment vendor's MIBs into the management
system's MIB repository. In most cases, these MIBs are downloadable from the
vendor's Web site.
The MIB type also contributes to its global ID. In accordance with the SMI, all of the
MIB types are uniquely identified through the use of the ISO/ITU-T global naming
tree, which is illustrated in Figure 11.3. To access any MIB object data value, its
global OID is used to retrieve the information. This can be accomplished by using
one of two methods. The OID can be called using a text string naming the whole tree
path or using the dotted integer form. To access the sysContact object in the MIB-2
module using the named form, the request would look like this: