Reference Guide

Link Layer Discovery Protocol | 401
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
fnC0057mp
Chassis ID
7 bits
9 bits
1 octet
1- 255 octets
TLV Type
(1-127)
TLV Length
Value
TLV Header
0-511 octets