HP 1920 Gigabit Ethernet Switch Series User Manual page 231

Field
Data
FCS
LLDP frames encapsulated in SNAP
•
Figure 196 LLDP frame encapsulated in SNAP
Table 70 Fields in a SNAP-encapsulated LLDP frame
Field
Destination MAC address
Source MAC address
Type
Data
FCS
LLDPDUs
LLDP uses LLDPDUs to exchange information. An LLDPDU comprises multiple TLVs. Each TLV carries a type
of device information, as shown in
Figure 197 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:
Description
LLDPDU.
Frame check sequence, a 32-bit CRC value used to determine the
validity of the received Ethernet frame.
Description
MAC address to which the LLDP frame is advertised. It is fixed to
0x0180-C200-000E, a multicast MAC address.
MAC address of the sending port. If the port does not have a MAC
address, the MAC address of the sending bridge is used.
SNAP type for the upper layer protocol. It is
0xAAAA-0300-0000-88CC for LLDP.
LLDPDU.
Frame check sequence, a 32-bit CRC value used to determine the
validity of the received Ethernet frame.
Figure 197.
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