About the SNMP Management Information Base (MIB)

The MIB contains the essential objects that make up the management information for the device. The Internet TCP/IP MIB, commonly referred to as MIB-II, defines the network objects to be managed for a TCP/IP network and provides a standard format for each object.

The MIB is structured as a hierarchical object tree divided into logically related groups of objects. For example, MIB-II contains the following groups of objects:

System. Contains general information about the device, for example: sysDescr (description), sysContact (person responsible), and sysName (device name).
Interfaces. Contains information about network interfaces, such as Ethernet adapters, or point-to-point links; for example: ifDescr (name), ifOperStatus (status), ifPhysAddress (physical address), ifInOctets, and ifOutOctets (number of octets received and sent by the interface).
IP. Contains information about the processing of IP packets, such as routing table information: ipRouteDest (the destination), and ipRouteNextHop (the next hop of the route entry).
- Other groups provide information about the operation of a specific protocol, for example, tcp ,udp, icmp, snmp, and egp.
- The enterprise group contains vendor-provided objects that are extensions to the MIB.

Each object of the MIB is identified by a numeric object identifier (OID) and each OID can be referred to by its text label. For example, the system group contains an object named sysDescr, which provides a description of the device. The sysDescr object has the following object identifier:

iso.org.dod.Internet.mgmt.mib.system.sysDescr

1.3.6.1.2.1.1.1

This object identifier would be 1.3.6.1.2.1.1.1 to which is appended an instance sub-identifier of 0. That is, 1.3.6.1.2.1.1.1.0 identifies the one and only instance of sysDescr.

All of the MIB-II objects (for TCP/IP networks) are under the "mib" sub tree (so all these objects will have an identifier that starts with 1.3.6.1.2.1).

For a detailed description of the MIB, see RFC 1213.