Dell PowerEdge FX2/FX2s - Manual (Page 138)

TLVs are encapsulated in a frame called an LLDP data unit (LLDPDU), which is transmitted from one
LLDP-enabled device to its LLDP-enabled neighbors. LLDP is a one-way protocol. LLDP-enabled devices
(LLDP agents) can transmit and/or receive advertisements, but they cannot solicit and do not respond to
advertisements.
There are five types of TLVs (as shown in the below table). All types are mandatory in the construction of
an LLDPDU except Optional TLVs. You can configure the inclusion of individual Optional TLVs.
Type, Length, Value (TLV) Types
Type TLV Description
0 End of LLDPDU Marks the end of an LLDPDU.
1 Chassis ID The Chassis ID TLV is a mandatory TLV that identifies the chassis
containing the IEEE 802 LAN station associated with the
transmitting LLDP agent.
2 Port ID The Port ID TLV is a mandatory TLV that identifies the port
component of the MSAP identifier associated with the transmitting
LLDP agent.
3 Time to Live The Time To Live TLV indicates the number of seconds that the
recipient LLDP agent considers the information associated with
this MSAP identifier to be valid.
— Optional Includes sub-types of TLVs that advertise specific configuration
information. These sub-types are Management TLVs, IEEE 802.1,
IEEE 802.3, and TIA-1057 Organizationally Specific TLVs.
Figure 20. LLDPDU Frame
Optional TLVs
The Dell Networking Operating System (OS) supports the following optional TLVs: Management TLVs,
IEEE 802.1 and 802.3 organizationally specific TLVs, and TIA-1057 organizationally specific TLVs.
138 Link Layer Discovery Protocol (LLDP)