Users Guide

TLVs are encapsulated in a frame called an LLDP data unit (LLDPDU) (shown in the following table), 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. All types are mandatory in the construction of an LLDPDU except Optional TLVs. You can configure the
inclusion of individual Optional TLVs.
Table 49. Type, Length, Value (TLV) Types
Type TLV Description
0 End of LLDPDU Marks the end of an LLDPDU.
1 Chassis ID An administratively assigned name that
identifies the LLDP agent.
2 Port ID An administratively assigned name that
identifies a port through which TLVs are
sent and received.
3 Time to Live An administratively assigned name that
identifies a port through which TLVs are
sent and received.
— 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 74. LLDPDU Frame
Optional TLVs
The Dell Networking OS supports these optional TLVs: management TLVs, IEEE 802.1 and 802.3 organizationally specific TLVs, and
TIA-1057 organizationally specific TLVs.
Management TLVs
A management TLV is an optional TLVs sub-type. This kind of TLV contains essential management information about the sender.
Organizationally Specific TLVs
A professional organization or a vendor can define organizationally specific TLVs. They have two mandatory fields (as shown in the
following illustration) in addition to the basic TLV fields.
Figure 75. Organizationally Specific TLV
448
Link Layer Discovery Protocol (LLDP)