LLDP is a protocol standardize in the 802.1AB standard. It works on layer two of the ISO/OSI layer model and allows the exchange of information between neighboring network devices. The information receive can be store in a management information base. Typical applications are network management or troubleshooting. The abbreviation LLDP stands for Link-Layer Discovery Protocol. It is a manufacturer-independent protocol that works on South Korean Phone Number List Layer 2 of the ISO/OSI layer model and is standardize in the IEEE 802.1AB standard. The protocol competes with manufacturer-specific solutions such as the Cisco Discovery Protocol (CDP).
The Link Layer Discovery Protocol allows various information to be exchange between neighboring network devices. To do this, the end devices periodically send Layer 2 frames with information about themselves to a multicast address. Other devices in this Layer 2 segment can receive this information and store it in a Management Information Base (MIB). The MIB can be read using SNMP (Simple Network Management Protocol).
The messages are sent and receive independently of each other, since no explicit connections are establish between the sending and receiving devices. Typical applications of the Link-Layer Discovery Protocol are network management, troubleshooting or the automatic detection of devices in a network such as VoIP phones.
The basic functionality of the Link-Layer Discovery Protocol
On devices that support the Link Layer Discovery Protocol, software, a so-call LLDP agent, is directly integrat or subsequently installed. The agent sends information about the device at cell phone number listing periodic intervals and receives LLDP frames from neighboring devices. There is no acknowledgement or dedicate connection setup between the sending and receiving devices. The information is packe in an Ethernet frame.
The frames contain an LLDP data unit (LLDPDU) of define length and structure. The Ethernet frames are addressed at MAC level to the multicast address 01:80:C2:00:00:0E. The LLDPDUs contain information about, for example: The receiving devices store this information in a local Management Information Base, which can be querie by external devices via the Simple Network Management Protocol.
Typical Applications of the Link-Layer Discovery Protocol
The Link-Layer Discovery Protocol can be use for various applications. The protocol can be use to manage and monitor networks, capture topologies, perform network inventories, find Bulk Database and resolve problems, or automatically detect certain devices. The Link-Layer Discovery Protocol is also use to compare PoE capabilities and PoE ( Power over Ethernet ) requirements.
There is an extension of the Link Layer Discovery Protocol specifically for the Voice over IP (VoIP) environment. It is call LLDP-MED (Link Layer Discovery Protocol – Media Endpoint Devices) and is use to detect VoIP devices and support their interoperability. This protocol can, for example:
Collect manufacturer information, hardware versions and other characteristics of VoIP devices
