Which statement accurately defines LLDP?

LLDP, or Link Layer Discovery Protocol, is fundamentally a Layer 2 discovery protocol. This means it operates at the Data Link layer of the OSI model, facilitating the discovery of neighboring devices on a local network. LLDP works by transmitting periodic advertisements (also known as LLDPDU - LLDP Data Units) over Ethernet frames, allowing devices to identify each other, exchange capabilities, and gather information about their ports and devices.

This Layer 2 functionality is crucial for network management and topology awareness, enabling devices to understand the physical layout of the network and improving troubleshooting and configuration management processes. By adhering to the IEEE 802.1AB standard, LLDP provides significant interoperability among different vendors' equipment, which is beneficial in heterogeneous networking environments.

Other options do not accurately reflect LLDP's characteristics. For example, labeling it as a Layer 3 discovery protocol misrepresents its operating level. Additionally, LLDP does not utilize TCP for communication; instead, it relies on Ethernet frames for its service delivery. Finally, the assertion that LLDP is not used in modern networks undervalues its importance, as it remains a widely adopted standard for network device discovery and management today.