Field

Description

FCS

Frame check sequence, a 32-bit CRC value used to determine the validity of

the received Ethernet frame.

 

 

 

Table 57 SNAP-encapsulated LLDPDU format

b.SNAP-encapsulated LLDPDU format

3.Fields in a SNAP encapsulated LLDPDU

Field

Description

Destination MAC address

The MAC address to which the LLDPDU is advertised. It is fixed to

0x0180-C200-000E, a multicast MAC address.

 

 

 

Source MAC address

The MAC address of the sending port. If the port does not have a MAC

address, the MAC address of the sending bridge is used.

 

 

 

Type

The SNAP-encoded LLDP Ethernet 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 comprises multiple TLV sequences. Each carries a specific type of device information, as shown in a.

a.LLDPDU encapsulation format

An LLDPDU can carry up 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

TLVs are type, length, and value sequences that carry information elements. The type field identifies the type of information, the length field indicates the length of the information field in octets, and the value field contains the information itself.

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