Introduction To Mib - Digitalchina Networks DCS-3950 series Manual

5.4.2 Introduction to MIB

The network management information accessed by NMS is well defined and
organized in a Management Information Base (MIB). MIB is pre-defined information which
can be accessed by network management protocols. It is in layered and structured form.
The pre-defined management information can be obtained from monitored network
devices. ISO ASN.1 defines a tree structure for MID. Each MIB organizes all the available
information with this tree structure. And each node on this tree contains an OID (Object
Identifier) and a brief description about the node. OID is a set of integers divided by
periods. It identifies the node and can be used to locate the node in a MID tree structure,
shown in the figure below:
In this figure, the OID of the object A is 1.2.1.1. NMS can locate this object through this
unique OID and gets the standard variables of the object. MIB defines a set of standard
variables for monitored network devices by following this structure.
If the variable information of Agent MIB needs to be browsed, the MIB browse
software needs to be run on the NMS. MIB in the Agent usually consists of public MIB and
private MIB. The public MIB contains public network management information that can be
accessed by all NMS; private MIB contains specific information which can be viewed and
controlled by the support of the manufacturers
MIB-I [RFC1156] is the first implemented public MIB of SNMP, and is replaced by
MIB-II [RFC1213]. MIB-II expands MIB-I and keeps the OID of MIB tree in MIB-I. MIB-II
contains sub-trees which are called groups. Objects in those groups cover all the
functional domains in network management. NMS obtains the network management
information by visiting the MIB of SNMP Agent.
The switch can operate as a SNMP Agent, and supports both SNMP v1/v2c and
SNMP v3. The switch supports basic MIB-II, RMON public MIB and other public MID such
DCS-3950 series Ethernet switch manual
Fig 5-1 ASN.1 Tree Instance
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