Lldp; Overview Of Lldp; Lldp Operation - GE PACSystems RXi User Manual

LLDP

12.2
The PNC implements the Link Layer Discovery Protocol (LLDP). A PROFINET IO-Supervisor
or other network host may use LLDP to discover the PROFINET network.

12.2.1 Overview of LLDP

The Link Layer Discovery Protocol is an IEEE standardized protocol used by network devices
to advertise their identity and capabilities and receive that information from physically
adjacent link layer peers. LLDP data packets are sent by devices from each of their interfaces
at fixed intervals. The LLDP packets are multicast and are not forwarded by network
switches.
Each LLDP packet consists of one LLDP Data Unit (LLDPDU). Each LLDPDU is a sequence
of Type-Length-Value (TLV) structures.
LLDP Data Unit Contents
Chassis ID TLV structure (mandatory, always first)
Port ID TLV structure (mandatory, always second)
Time to Live TLV structure (mandatory, always third)
End of PDU TLV (mandatory, always last)

12.2.2 LLDP Operation

The LLDP agent in the PNC multicasts LLDP messages to the network at 5 second intervals,
or when a change occurs in any of the local data that is delivered within the LLDP message.
The LLDP messages are transmitted from each external port that is connected to a network.
GFK-2816F
Optional Structures (any number of these, in any order)
August 2015
Chapter 12. PROFINET Network Management
.
.
.
229