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- [Instructor] In managing a sizable network,

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Simple Network Management Protocol or SNMP

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is a handy thing to have.

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SNMP defines mechanisms for implementing various features

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needed for maintaining networks,

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including securing them.

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SNMP specifies the standards

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on how to collect network device data.

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It also covers the ability

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to control network devices remotely.

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SNMP implementations allow you

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to monitor the health of network devices too.

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All these capabilities are necessary

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to enhance network security.

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SNMP consists of agent,

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manager,

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management information base,

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or MIB,

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and managed device.

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An agent collects the device data

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from an SNMP-managed device.

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It receives commands from a manager and executes them.

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A manager controls a managed device through an agent.

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It obtains data from an agent.

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Management Information Base or MIB stores the SNMP data.

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A managed device is controlled by an agent.

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Therefore, the managed device is an SNMP information source.

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Most of the time agents just receive commands

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from their managers,

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but sometimes they also send messages

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back to their managers.

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These messages sent back to the managers are called traps.

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These are alerts sent by the agents

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when there are errors or problems on a managed device.

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In summary, you have a managed device in SNMP

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such as a server or switch.

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Agents sit on top of it.

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There's another host on which a manager runs

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and the manager talks to the agent

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and receives data by using a Get command.

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It also controls the agent through a Set command.

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An agent sometimes sends messages to its manager

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and these messages are called traps.

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MIB is a database used by the SNMP manager host.