Connectivity Guide

Table Of Contents
Figure 78. Type, Length, Value (TLV) Segment
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 51. Type, Length, Value (TLV) Types
Type TLV Description
0 End of LLDPDU Marks the end of a 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 79. LLDPDU Frame
Link Layer Discovery Protocol (LLDP)
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