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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 envi-
ronment, 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 con-
trolled by the agent over the network.
The software used to access the information maintained by the
SNMP agents is referred to as the manager. This software typi-
cally runs on a network-attached station and can manage a
number of agents at once. The manager software uses a 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 for-
mat 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 opera-
tions. Operations that change a functional parameter 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 the manager soft-
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MANAGING VIA SNMP AND RMON