User’s Manual of IGS-20040MT
4.3 Simple Network Management Protocol
4.3.1 SNMP Overview
The Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management
information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite.
SNMP enables network administrators to manage network performance, find and solve network problems, and plan for network
growth.
An SNMP-managed network consists of three key components: Network management stations (NMSs), SNMP agents,
Management information base (MIB) and network-management protocol
：
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Network management stations (NMSs)
：
Sometimes called consoles, these devices execute management applications
that monitor and control network elements. Physically, NMSs are usually engineering workstation-caliber computers with
fast CPUs, megapixel color displays, substantial memory, and abundant disk space. At least one NMS must be present in
each managed environment.
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Agents
：
Agents are software modules that reside in network elements. They collect and store management information
such as the number of error packets received by a network element.
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Management information base (MIB)
：
A MIB is a collection of managed objects residing in a virtual information store.
Collections of related managed objects are defined in specific MIB modules.
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Network management protocol
：
A management protocol is used to convey management information between agents
and NMSs. SNMP is the Internet community's de facto standard management protocol.
SNMP Operations
SNMP itself is a simple request/response protocol. NMSs can send multiple requests without receiving a response.
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Get --
Allows the NMS to retrieve an object instance from the agent.
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Set --
Allows the NMS to set values for object instances within an agent.
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Trap --
Used by the agent to asynchronously inform the NMS of some event. The SNMPv2 trap message is designed to
replace the SNMPv1 trap message.
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