LLDP stands for Link Layer Discovery Protocol. It's a vendor-neutral, standards-based Layer 2 network protocol that serves a similar purpose to Cisco Discovery Protocol (CDP). LLDP is defined by the IEEE 802.1AB standard and is used to discover and share information about neighbouring devices on a local area network (LAN). Unlike CDP, which is specific to Cisco devices, LLDP is designed to work across a variety of networking equipment from different manufacturers.

Here's how does LLDP work:

Neighbour Discovery: Just like CDP, LLDP enables devices to advertise information about themselves to neighbouring devices. When a device is powered on or a new connection is established, it sends out LLDP advertisements to its directly connected neighbours.

Information Exchange: LLDP advertisements include information about the sending device, such as its system name, system description, system capabilities, management IP address, and more. This information helps administrators identify and understand the characteristics of neighbouring devices.

Vendor Neutrality: LLDP is designed to work across different vendors' networking equipment. This means that devices from different manufacturers can exchange information using LLDP, promoting interoperability in mixed-vendor environments.

Topology Discovery: LLDP information can be used to build a network topology map, illustrating how devices are interconnected at the Layer 2 level. This can aid network administrators in understanding their network layout.

Network Monitoring and Troubleshooting: LLDP information is also valuable for monitoring and troubleshooting purposes. Knowing which devices are connected to each switch port helps administrators diagnose network issues and plan network changes.

LLDP has gained popularity as organizations have embraced multi-vendor environments and the need for standardization and interoperability has grown. It's widely supported in various network devices, including switches, routers, access points, and other networking equipment.

In summary, LLDP is a standardized protocol that provides a means for devices to discover and share information about their neighbours on a network, facilitating better understanding, management, and troubleshooting of network infrastructures.