Which three circumstances trigger Layer 2 polling of infrastructure devices?

A. Manual Polling: This is when an administrator or network operator initiates a poll manually to gather information or check the status of the network devices. This can be done for immediate troubleshooting or assessment.

B. Scheduled Poll Timings: Network management systems often have the capability to schedule regular polls of devices to check their status or monitor their performance. These scheduled polls can be set at regular intervals (such as every few minutes, hours, or daily) depending on the requirements of the network.

E. Linkup and Linkdown Traps: SNMP (Simple Network Management Protocol) traps, like Linkup and Linkdown, are automated notifications sent from network devices to a management system. A Linkup trap indicates that a particular interface has become active (up), while a Linkdown trap indicates that an interface has become inactive (down). These traps can trigger Layer 2 polling to ascertain the current status of network interfaces and devices.