Think of SNMP traps like an emergency alert system for your network. Just as a smoke detector doesn't wait to be asked if there's a fire - it immediately alerts you when it detects smoke - an SNMP trap is a proactive notification mechanism where network devices take the initiative to report important events without being asked.
This is fundamentally different from normal SNMP operations, where a management system regularly polls devices for information (known as SNMP GET requests). To understand the distinction, imagine you're monitoring a server room:
Regular SNMP polling would be like a security guard doing scheduled walk-throughs every hour to check if everything is okay. In contrast, an SNMP trap would be like a device immediately calling the security guard's phone when something goes wrong, without waiting for the next scheduled check.
Some common scenarios where devices might send SNMP traps include:
> When a network interface goes down
> If temperature exceeds safe thresholds
> When available disk space drops below critical levels
> If someone attempts unauthorized access
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A) Describes the polling process, where the management station actively requests information from devices.
B) Refers to community strings, which are used for authentication in SNMP but are unrelated to traps.
D) Pertains to security enhancements in SNMP (like SNMPv3) but does not describe what a trap is.