Administrator Guide
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Link Layer Discovery Protocol (LLDP)
Link layer discovery protocol (LLDP) advertises connectivity and management from the local station to the adjacent stations on an
IEEE 802 LAN.
LLDP facilitates multi-vendor interoperability by using standard management tools to discover and make available a physical topology
for network management. The Dell Networking operating software implementation of LLDP is based on IEEE standard 801.1ab.
The starting point for using LLDP is invoking LLDP with the protocol lldp command in either CONFIGURATION or INTERFACE mode.
The information LLDP distributes is stored by its recipients in a standard management information base (MIB). You can access the
information by a network management system through a management protocol such as simple network management protocol
(SNMP).
An Aggregator auto-congures to support the link layer discovery protocol (LLDP) for the auto-discovery of network devices. You
can use CLI commands to display acquired LLDP information, clear LLDP counters, and debug LACP operation.
Supported Modes
Standalone, PMUX, VLT, Stacking
Protocol Data Units
Conguration information is exchanged in the form of type, length, value (TLV) segments. The below gure shows the chassis ID
TLV.
• Type — Indicates the type of eld that a part of the message represents.
• Length — Indicates the size of the value eld (in byte).
• Value — Indicates the data for this part of the message.
Figure 20. Type, Length, Value (TLV) Segment
TLVs are encapsulated in a frame called an LLDP data unit (LLDPDU), which is transmitted from one LLDP-enabled device to its
LLDP-enabled neighbors. LLDP is a one-way protocol. LLDP-enabled devices (LLDP agents) can transmit and/or receive
advertisements, but they cannot solicit and do not respond to advertisements.
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Link Layer Discovery Protocol (LLDP)