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Configuring LLDP
Overview
In a heterogeneous network, a standard configuration exchange platform makes sure different types of
network devices from different vendors can discover one another and exchange configuration.
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 as TLV (type, length, and value) triplets in LLDP Data Units (LLDPDUs) to the
directly connected devices. Local device information includes its system capabilities, management IP
address, device ID, port ID, and so on. The device stores the device information in LLDPDUs from the LLDP
neighbors in a standard MIB. LLDP enables a network management system to quickly detect and identify
Layer 2 network topology changes.
For more information about MIBs, see "Configuring SNMP."
Basic concepts
LLDP frame formats
LLDP sends device information in LLDP frames. LLDP frames are encapsulated in Ethernet II or SNAP
frames.
• LLDP frames encapsulated in Ethernet II
Figure 195 LLDP frame encapsulated in Ethernet II
Table 69 Fields in an Ethernet II encapsulated LLDP frame
Field Descri
Destination MAC address
MAC address to which the LLDP frame 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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