Cisco Certified Network Professional 2025 – 400 Free Practice Questions to Pass the Exam

The command used to enable Link Layer Discovery Protocol (LLDP) on a Cisco switch is "lldp run." This command is integral to initiating LLDP, which is a protocol used for network devices to advertise their identity and capabilities on a local area network. By enabling LLDP with this command, the switch can send and receive LLDP packets, allowing it to discover other LLDP-enabled devices connected to it.

When LLDP is activated using "lldp run," it allows the switch to gather information about neighboring devices, such as their device type, software version, and other relevant management addresses, which facilitates better network management and device troubleshooting. This command essentially turns on the LLDP feature, enabling a network administrator to better understand the topology and connected devices.

The other options do not correspond to valid commands within IOS for enabling LLDP, and thus they would not accomplish the task. This highlights the specificity required in Cisco’s command-line interface, where knowing the correct command is crucial for efficient network management.