H3C Technologies H3C S10500 Series Switches - Manual (Page 231)

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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
TLVs are type, length, and value sequences that carry information elements. The type field identifies the
type of information, the length field measures the length of the information field in octets, and the value
field contains the information itself.
LLDPDU TLVs fall into 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. Organizationally specific TLVs and
LLDP-MED TLVs are used for enhanced device management; they are defined by standardization or other
organizations and are optional to LLDPDUs.
1. Basic management TLVs
Table 24 lists the basic management TLV types. Some of them are mandatory to LLDPDUs, that is, must
be included in every LLDPDU.
Table 24 Basic management TLVs
Type Description Remarks
Chassis ID Specifies the bridge MAC address of the sending device
Port ID
Specifies the ID of the sending port
If the LLDPDU carries LLDP-MED TLVs, the port ID TLV carries the
MAC address of the sending port or the bridge MAC if the port
does not have a MAC address. If the LLDPDU carries no LLDP-MED
TLVs, the port ID TLV carries the port name.
Time To Live
Specifies the life of the transmitted information on the receiving
device
End of LLDPDU Marks the end of the TLV sequence in the LLDPDU
Mandatory
Port Description Specifies the port description of the sending port
System Name Specifies the assigned name of the sending device
System Description Specifies the description of the sending device
System Capabilities
Identifies the primary functions of the sending device and the
enabled primary functions
Management Address
Specifies the management address, and the interface number and
object identifier (OID) associated with the address
Optional
2. IEEE 802.1 organizationally specific TLVs
Table 25 IEEE 802.1 organizationally specific TLVs
Type Description
Port VLAN ID
Specifies the port’s VLAN identifier (PVID). An LLDPDU carries only one TLV of
this type.