Hello,

Can someone help me to understand the difference between SNMP and SNMP trap? Whether we need to configure any community string for enabling the SNMP TRAP?

SNMP is the protocol, and the community string is for enabling SNMP. An SNMP trap is a way for an SNMP agent to collect particular data and notify the management station.

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094aa5.shtml

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Thanks for the reply.

I read that SNMP Management station and agent should use the same community string (Both RO and RW). what about the SNMP TRAP, how we need to configure the community string for SNMP trap?

You configure the trap on the agent. That way the agent can monitor the particular trap.

For example, on a cisco router, you can setup an SNMP trap for OSPF LSAs, by:



Now the agent can report information on OSPF LSAs.

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oh.... thanks a lot hunter_thom

so...the community string comes into the picture only when we are configuring the SNMP alone. right? PLease corrct me if i'm wrong.

Right, the community string is for configuring SNMP, not when configuring the SNMP traps. Only when setting up an agent and a management station will the community string come into play.

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okay.... I got it

Great. Hope it helped.

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The below is one of eg: which i took it from Cisco site. Can u help me to understand what the keyword "PUBLIC" will do in this config.

This example enables the router to send all traps to the host myhost.cisco.com with the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com public

That is the community string. They must match on agent and manager for the SNMP reporting to be sent to the manager.

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SNMP is used to collect information from a device. Usually monitoring tools use snmp to check the status of an interface or the devices health. When the data is collected is completely dependent and controlled by the "poller" or server sending the snmp request.

SNMP TRAPs are alerts sent from a device to a monitoring server once an alarm is triggered. So if an interface goes down then a trap is sent to the monitoring server saying its down. With basic snmp setup the monitoring server would not know about the downed port until it polls the device for the port status.

Hope this helps clarify.

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