Get/Set Operations - D-Link D-View 5.1 User Manual

D-View 5.1 User's Guide
information, called MIB objects, are kept in an SNMP device, where they can be readily
accessed and modified by the device agent at the request of the network administrator.
Basically, management is achieved through transactions between the SNMP agent on
the device and the management console. The management console sends SNMP
request packets to the agent, which in turn complies by sending response packets.
There are five types of SNMP requests: Get, GetNext, GetResponse, Set, and Trap. The
following describes some of the requests supported by the system:
GET – This request queries the SNMP agent for the current value of one or more MIB
objects in an SNMP device. The agent retrieves the values of the requested objects and
then sends them to the management console.
SET – This request asks the SNMP agent to modify the value of one or more MIB
objects in an SNMP device. Be reminded that MIB objects can be read-only, read-write,
write-only, or not-accessible. Read-only MIBs are either fixed constants or changing
variables such as the number of ports in a bridge or hub and number of packets
passing through a port. Read-write MIBs are variables usually related to user-
configurable parameters such as the IP address and name of the device. Since you can
only set read-write and write-only MIB objects, the SET request therefore can only be
used on these types of objects.
MIB objects are logically arranged in a hierarchy called a MIB tree structure. The name
of each MIB object, called MIB object ID, in the hierarchy is the sequence of numeric
labels on the nodes along a path from the root down to the actual MIB object. The
actual MIB object is the last node in the path.

GET/SET Operations

When the management console needs to retrieve the value of a particular MIB object
from an SNMP device, it sends a GET request to the device SNMP agent and the
numerical representation of the target MIB object. For example: if the management
console wants to retrieve the value of the MIB object ipInReceives from a device, it
sends a GET request to the device SNMP agent followed by the numerical
representation of the MIB object, which is 1.3.6.1.2.1.4.3.0. The agent uses this value
to search for the corresponding value of the specified MIB object and then sends the
value to the requesting management console.
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