How SNMP works
SNMP is an open network management
technology that permits monitoring and control
of a network in a vendor-independent manner. It enables
the network administrator to effectively
manage the various network components using a set of
well-known procedures understood by all components, irrespective
of the vendor that manufactured them. It is commonly
used to manage TCP/IP based networks
and is a published full standard in the Internet community.
SNMP is not limited to management of a
single network; it can also be
used to manage a collection of several networks connected
together, called an internetwork or in short, internet.
There are three basic components of SNMP: the protocol itself, described in detail in RFC 1157; SMI, the Structure of Management Information (RFC 1155); and MIB, the Management Information Base (RFCs 1156 and 1213).
Systems using SNMP are divided into two categories: management stations (sometimes called ``clients'') and agents (sometimes called ``servers''). The management station is the system that issues a query; the agent is the system that is being queried. Queries are sent and received in the form of Protocol Data Units (PDUs).
SNMP uses object identifiers (OIDs) to provide variables with a name that both the management station and the agent can understand. The Structure of Management Information (SMI) provides a set of rules used in defining objects. A scheme by which objects are grouped together for easier reference is known as a Management Information Base (MIB).
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