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Configuring LLDP
Overview
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 Link Layer Discovery Protocol (LLDP) is specified 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 LLDP 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). For more information about MIBs, see "Configuring
SN
MP." LLDP enables a network management system to quickly detect and identify Layer 2 network
topology changes.
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. LLDPDUs encapsulated in Ethernet II
Figure 201 LLDPDU encapsulated in Ethernet II
Table 70 Description of the fields in an Ethernet II encapsulated LLDPDU
Field Descri
Destination MAC address
MAC address to which the LLDPDU is advertised. It is fixed to
0x0180-C200-000E, a multicast MAC address.
Source MAC address MAC address of the sending port.
Type Ethernet type for the upper layer protocol. It is 0x88CC for LLDP.
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