Definition
Link layer discovery protocol (LLDP) is a standardized network protocol for identifying and discovering devices within a local area network (LAN). It is commonly used in enterprise network devices such as routers, switches, and wireless access points.
LLDP helps network administrators manage and troubleshoot networks. It enables network devices, like routers and switches, to share their identities, capabilities, and details about nearby devices. This is important for understanding connections and layout within a network.
How LLDP Works
- Network devices embedded with LLDP send packets with information about themselves and listen for packets from other devices on the network.
- The devices share information such as port descriptions, identifiers, system capabilities, and network management addresses. This data is hosted on local databases and can be accessed through network management systems.
- LLDP updates the data regularly to ensure the network map is up-to-date.
LLDP Advantages and Disadvantages
LLDP significantly streamlines network management and offers a clear view of the network’s physical topology, making documentation and troubleshooting easy. However, because it only operates at the link layer, it doesn’t offer advanced network structure information such as routing details or IP addressing schemes.
LLDP Applications
- Ethernet-connected devices: LLDP helps to facilitate the management of network resources and streamline networking tasks for administrators in a multivendor network.
- Security: Advertising device information through LLDP helps network administrators detect rogue or unauthorized devices on the network. They can then quarantine or block these devices to prevent threats.
