PLANET GSW-1602SF - Manual (Page 44)

User’s Manual of GSW-1602SF / GSW-2404SF
4.3 SNMP
4.3.1 Theory
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：
„ 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.
„ 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.
„ 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.
„ 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.
„ Get -- Allows the NMS to retrieve an object instance from the agent.
„ Set -- Allows the NMS to set values for object instances within an agent.
„ 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.
SNMP community
An SNMP community is the group that devices and management stations running SNMP belong to. It helps define where
information is sent. The community name is used to identify the group. A SNMP device or agent may belong to more than
one SNMP community. It will not respond to requests from management stations that do not belong to one of its
communities. SNMP default communities are:
。 Write = private
。 Read = public
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