Dell MX5108n OS10 Enterprise Edition User Guide for PowerEdge MX IO Modules Re - Page 184

LAN devices transmit LLDPDUs, which encapsulate TLVs, to neighboring LAN devices. LLDP is a one-way protocol and LAN devices (LLDP agents) transmit and/or receive advertisements but they cannot solicit and do not respond to advertisements. There are three mandatory TLVs followed by zero or more optional TLVs and the end of the LLDPDU TLV. The three mandatory TLVs must be located at the beginning of the LLDPDU in the following order: • Chassis ID TLV • Port ID TLV • Time-to-live TLV 0 - End of LLDPDU Marks the end of an LLDPDU. 1 - Chassis ID Identifies the LAN agent. 2 - Port ID Identifies a port through which the LAN device transmits LLDPDUs. 3 - Time-to-live Number of seconds that the recipient LLDP agent considers the information associated with this MAP identifier to be valid. - Optional Includes sub-types of TLVs that advertise specific configuration information. These sub-types are management TLVs, IEEE 802.1, IEEE 802.3, and TIA-1057 organization-specific TLVs. Optional TLVs OS10 supports basic TLVs, IEEE 802.1, and 802.3 organizationally-specific TLVs, and TIA-1057 organizationally-specific TLVs. A basic TLV is an optional TLV sub-type. This kind of TLV contains essential management information about the sender. A professional organization or vendor can define organizationally-specific TLVs. They have two mandatory fields, in addition to the basic TLV fields. 184 Layer 2