SNMP Protocol
SNMP (Simple Network Management Protocol) is a communica-
tion protocol designed specifically for the purpose of managing
devices or other elements on a network. Network equipment
commonly managed with SNMP includes hubs, switches,
bridges, routers and host computers. SNMP is typically used to
configure these devices for proper operation in a network
environment, as well as monitor them to evaluate performance
and detect potential problems.
Managed entities supporting SNMP typically contain software
which runs locally on the device and is referred to as an agent.
The agent monitors and allows control of the functionality of
the device. A defined set of variables, referred to as objects, is
maintained by the agent and used to manage the device. These
objects are defined in a Management Information Base (MIB)
which allows for a standard presentation of information
controlled by the agent over the network.
The software used to access the information maintained by the
SNMP agent is referred to as the manager. This software
typically runs on a network-attached station and can manage a
number of agents at once. The management software uses an
MIB specification, equivalent to that which the agent maintains,
to read and write objects controlled by the agent for purposes
of configuring and monitoring the device. SNMP defines the
format of the MIB specifications and the protocol used to access
this information.
There are three main operations defined in SNMP. Operations
which read information from the managed device, such as may
be used to obtain status or statistical data, are called
GET operations. Operations that change a functional parame-
ter on the device, such as may be used to configure security
access to the device or to initiate a self test, are referred to as
SET operations. GET and SET operations are initiated only by
MANAGEMENT VIA SNMP
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