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LLDP configuration
Overview
Background
In a heterogeneous network, a standard configuration exchange platform ensures that different types of
network devices from different vendors can discover one another and exchange configuration for the sake
of interoperability and management.
The IETF drafted the Link Layer Discovery Protocol (LLDP) in IEEE 802.1AB. The protocol operates on the
data link layer to exchange device information between directly connected devices. With LLDP, a device
sends local 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 the
directly connected devices. At the same time, the device stores the device information received in
LLDPDUs sent from the LLDP neighbors in a standard management information base (MIB). LLDP enables a
network management system to quickly and identify Layer-2 network topology change.
NOTE:
For more information about MIBs, see the
Network Management and Monitoring Configuration Guide
.
Basic concepts
LLDPDU formats
LLDP sends device information in LLDP data units (LLDPDUs). LLDPDUs are encapsulated in Ethernet II or
Subnetwork Access Protocol (SNAP) frames.
1. Ethernet II-encapsulated LLDPDU format
Figure 54 Ethernet II-encapsulated LLDPDU format
Data = LLDPU
(1500 bytes)
0
Destination MAC address
Source MAC address
Type
15 31
FCS
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