Configuring Lldp; Overview; Background; Basic Concepts - HP 5120 EI Series Lan Switching Configuration Manual

Configuring LLDP

Overview

Background

In a heterogeneous network, a standard configuration exchange platform ensures that different types of
network devices from different vendors can discover one another and exchange configuration for the
sake of interoperability and management.
The Link Layer Discovery Protocol (LLDP) is specified in IEEE 802.1AB. The protocol operates on the data
link layer to exchange device information between directly connected devices. With LLDP, a device sends
local device information (including its major functions, management IP address, device ID, and port ID)
as TLV (type, length, and value) triplets in LLDP Data Units (LLDPDUs) to the directly connected devices. At
the same time, the device stores the device information received in LLDPDUs sent from the LLDP neighbors
in a standard management information base (MIB). For more information about MIBs, see Network
Management and Monitoring Configuration Guide. LLDP enables a network management system to
quickly detect and identify Layer 2 network topology changes.

Basic concepts

LLDPDU formats
LLDP sends device information in LLDPDUs. LLDPDUs are encapsulated in Ethernet II or Subnetwork
Access Protocol (SNAP) frames.
Ethernet II-encapsulated LLDPDU format
1.
Figure 64 Ethernet II-encapsulated LLDPDU format
Table 21 Fields in an Ethernet II-encapsulated LLDPDU
Field
Destination MAC address
Description
MAC address to which the LLDPDU is advertised. It is fixed to
0x0180-C200-000E, a multicast MAC address.
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