177
Field Description
FCS
Frame check sequence, a 32-bit CRC value used to determine the validity of
the received Ethernet frame.
• SNAP-encapsulated LLDP frame format
Figure 64 SNAP-encapsulated LLDP frame format
Table 22 Fields in a SNAP-encapsulated LLDP frame
Field Description
Destination MAC address
MAC address to which the LLDP frame is advertised. It is fixed at
0x0180-C200-000E, a multicast MAC address.
Source MAC address MAC address of the sending port.
Type
SNAP type for the upper layer protocol. It is 0xAAAA-0300-0000-88CC for
LLDP.
Data LLDPDU.
FCS
Frame check sequence, a 32-bit CRC value used to determine the validity of
the received Ethernet frame.
LLDPDUs
LLDP uses LLDPDUs to exchange information. An LLDPDU contains multiple TLVs. Each TLV
carries a type of device information, as shown in Figure 65.
Figure 65
LLDPDU encapsulation format
An LLDPDU can carry up to 28 types of TLVs. Mandatory TLVs include Chassis ID TLV, Port ID TLV,
Time to Live TLV, and End of LLDPDU TLV. Other TLVs are optional.
TLVs
A TLV is an information element that contains the type, length, and value fields.
LLDPDU TLVs include the following categories:
• Basic management TLVs
• Organizationally (IEEE 802.1 and IEEE 802.3) specific TLVs
• LLDP-MED (media endpoint discovery) TLVs
Basic management TLVs are essential to device management.
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