MIB
A Management Information Base (MIB) specifies variables (MIB object identifiers or OIDs) maintained by NEs. These variables can be queried and set in the management process. A MIB provides a structure that contains data on all NEs that may be managed on the network. The SNMP MIB uses a hierarchical tree structure similar to the Domain Name System (DNS), beginning with a nameless root at the top. Figure 1 shows an object naming tree, one part of the MIB.
The three objects at the top of the object naming tree are: ISO, ITU-T (formerly CCITT), and the sum of ISO and ITU-T. There are four objects under ISO. Of these, the number 3 identifies an organization. A Department of Defense (DoD) sub-tree, marked dod (6), is under the identified organization (3). Under dod (6) is internet (1). If the only objects being considered are Internet objects, you may begin drawing the sub-tree below the Internet object (the square frames in dotted lines with shadow marks in the following diagram), and place the identifier {1.3.6.1} next to the Internet object.
One of the objects under the Internet object is mgmt (2). The object under mgmt (2) is mib-2 (1) (formerly renamed in the new edition MIB-II defined in 1991). mib-2 is identified by an OID, {1.3.6.1.2.1} or {Internet(1).2.1}.
Type |
Identifier |
Information |
|---|---|---|
system |
1 |
Operating system of a host or router |
interfaces |
2 |
Various types of network interfaces and traffic volumes on these interfaces |
address translation |
3 |
Address translation (such as ARP mapping) |
ip |
4 |
Internet software (for collecting statistics about IP fragments) |
Internet Control Message Protocol (icmp) |
5 |
ICMP software (for collecting statistics about received ICMP messages) |
TCP |
6 |
TCP software (for algorithms, parameters, and statistics) |
UDP |
7 |
UDP software (for collecting statistics on UDP traffic volumes) |
External Gateway Protocol (EGP) |
8 |
EGP software (for collecting statistics on EGP traffic) |
MIB is defined independently of a network management protocol. Device manufacturers can integrate SNMP agent software into their products (for example, routers), but they must ensure that this software complies with relevant standards after new MIBs are defined. You can use the same network management software to manage routers containing different MIB versions. However, the network management software cannot manage a router that does not support the MIB function.