Reference Guide

Link Layer Discovery Protocol | 409
21
Link Layer Discovery Protocol
Link Layer Discovery Protocol is supported only on platforms: c e s
This chapter contains the following sections:
• 802.1AB (LLDP) Overview
• TIA-1057 (LLDP-MED) Overview
• Configuring LLDP
802.1AB (LLDP) Overview
Link Layer Discovery Protocol (LLDP)—defined by IEEE 802.1AB—is a protocol that enables a LAN
device to advertise its configuration and receive configuration information from adjacent LLDP-enabled
LAN infrastructure devices. The collected information is stored in a management information base (MIB)
on each device, and is accessible via SNMP.
Protocol Data Units
Configuration information is exchanged in the form of Type, Length, Value (TLV) segments. Figure 21-1
shows the Chassis ID TLV.
• Type—The kind of information included in the TLV
• Length—The value, in octets, of the TLV after the Length field
• Value—The configuration information that the agent is advertising
Figure 21-1. Type, Length, Value (TLV) Segment
Chassis ID Sub-type
fnC0057m
p
Chassis ID
7 bits
9 bits
1 octet
1- 255 octets
TLV Type
(1-127)
TLV Length
Value
TLV Header
0-511 octets