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56
SNMP O
VERVIEW
What Are MIB
Groups?
administrators to know how many sheets of paper were available in the printer
without physically moving to the printer. The system administrators would install
the Manager in these machines and query the printer agent to obtain this
information.
You can use the standard MIBs. For example, RFC1213-MIB is a standard MIB for
managing the system that each operating system implements. This MIB contains
information regarding the system and the number of interfaces. SNMP agents for
different types of devices provide access to objects that are specific to the type of
device.
To enable the SNMP manager or management application to operate intelligently
on the data available on the device, the Manager must know the names and types
of objects on the managed device. This is possible using MIB modules, which are
specified in MIB files provided with managed devices. For example, rfc1213-MIB
(also known as MIB-II) is a MIB module that is typically supported by all SNMP
agents on TCP/IP enabled devices or systems. This MIB file contains a description
of the object hierarchy on the managed device and the name (OID), syntax, and
access privileges for each variable in the MIB. For example, when the MIB module
is loaded in a MIB browser, the label of the variable, such as, sysDescr, can be
used to identify the variable, since the MIB browser can use the MIB module to
translate this label to an OID.
Only the types of objects on the managed device are specified by the MIB, and not
the specific objects (or instances). For example, ifInOctets in rfc1213-MIB specifies
a type of object for number of input octets on an interface, but the specific objects
or instances of that type are specified as ifInOctets.1or ifInOctets.2, depending on
the number of interfaces. When specifying an object to the SNMP agent, a proper
OID that includes the instance needs to be used by the manager. When not
properly specified, the agent responds with a
A MIB group is a collection of managed objects, and is represented by the name or
OID of a node in the OID tree. Groups may contain other groups. For example, bea
is a MIB group that is a member of the private.enterprises MIB group. The nodes in
the OID tree that are not groups - the base level of the OID tree - are the leaves of
the OID tree. For example, in the following diagram:
MIB group x contains a group of objects, a, b, and c.
•
•
MIB group y contains a group of objects, d, e, and f.
STRM SNMP Agent
No such variable
error.
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