H3C Technologies H3C S12500 Series Switches - Manual (Page 230)

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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 (LLDP frames) 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 LLDP frames from the
LLDP neighbors in a standard MIB. For more information about MIBs, see Network Management and
Monitoring Configuration Guide. LLDP enables a network management system to quickly detect and
identify Layer 2 network topology changes.
Basic concepts
LLDP frame formats
LLDP sends device information in LLDP frames. LLDP frames are encapsulated in Ethernet II or SNAP
frames.
1. Ethernet II-encapsulated LLDP frame
Figure 80 Ethernet II-encapsulated LLDP frame
Table 23 Fields in an Ethernet II-encapsulated LLDP frame
Field Description
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. This field is 0x88CC for LLDP.
Data LLDPDU.