Which statement best describes LLDP's function?

• A. It negotiates IP addresses using DHCP.
• B. Link Layer Discovery Protocol advertising device/port info to neighbors.
• C. It provides encryption for link-layer frames.
• D. It manages spanning-tree topology information.

Answer: (B)

LLDP is a data-link-layer protocol used to discover neighbors and share information about a device and its ports. It works by sending LLDPDataUnits that carry TLVs like chassis ID, port ID, system name/description, and capabilities. This allows neighboring devices to learn who is connected, what features are available, and how to reach each other, which supports network mapping, troubleshooting, and management.

DHCP handles IP address assignment, which is unrelated to LLDP. LLDP does not provide encryption for link-layer frames (that role is filled by technologies like MACsec). Spanning-tree topology management is handled by STP/RSTP/MSTP, not LLDP.