HP 6125XLG Configuration Manual page 244

LLDP frame encapsulated in SNAP
•
Figure 70 SNAP-encapsulated LLDP frame
Table 16 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 TLV sequences. Each TLV
carries a type of device information, as shown in
Figure 71 LLDPDU encapsulation format
An LLDPDU can carry up to 32 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.
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.
Description
MAC address to which the LLDP frame is advertised. It is the same as that
for Ethernet II-encapsulated LLDP frames.
MAC address of the sending port.
SNAP type for the upper layer protocol. This field is
0xAAAA-0300-0000-88CC for LLDP.
LLDPDU. An LLDP frame contains only one LLDPDU.
Frame check sequence, a 32-bit CRC value used to determine the validity
of the received Ethernet frame.
Figure 71.
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