154LLDP configurationThis chapter includes these sections:• Overview• LLDP configuration task list• Displaying and maintaining LLDP• LLDP configuration examplesOverviewBackgroundIn a heterogeneous network, it is important that different types of network devices from different vendorscan discover one another and exchange configuration for interoperability and management sake. Astandard configuration exchange platform was created.The Link Layer Discovery Protocol (LLDP) is specified in IEEE 802.1AB. The protocol operates on the datalink layer to exchange device information between directly connected devices. With LLDP, a device sendslocal device information (including its major functions, management IP address, device ID, and port ID)as TLV (type, length, and value) triplets in Link Layer Discovery Protocol Data Units (LLDPDUs) to thedirectly connected devices, and at the same time, stores the device information received in LLDPDUs sentfrom the LLDP neighbors in a standard management information base (MIB). It allows a networkmanagement system to fast detect Layer-2 network topology change and identify what the change is.NOTE:For more information about MIBs, see theNetwork Management and Monitoring Configuration Guide.Basic conceptsLLDPDUsLLDP sends device information in LLDP data units (LLDPDUs). LLDPDUs are encapsulated in Ethernet II orSubnetwork Access Protocol (SNAP) frames.1. Ethernet II-encapsulated LLDPDU format
