ZyXEL GS1920 Series User Guide - Page 251

LLDP-MED Overview

Page 251 highlights

Chapter 32 Link Layer Discovery Protocol (LLDP) Figure 183 LLDP Overview 32.2 LLDP-MED Overview LLDP-MED (Link Layer Discovery Protocol for Media Endpoint Devices) is an extension to the standard LLDP developed by the Telecommunications Industry Association (TIA) TR-41.4 subcommittee which defines the enhanced discovery capabilities, such as VoIP applications, to enable network administrators manage their network topology application more efficiently. Unlike the traditional LLDP, which has some limitations when handling multiple application devices, the LLDP-MED offers display of accurate physical topology, interoperability of devices, and easy trouble shooting for misconfigured IP addresses. There are three classes of endpoint devices that the LLDPMED supports: Class I: IP Communications Controllers or other communication related servers Class II: Voice Gateways, Conference Bridges or Media Servers Class III: IP-Phones, PC-based Softphones, End user Communication Appliances supporting IP Media The following figure shows that with the LLDP-MED, network connectivity devices (NCD) like Switches and Routers will transmit LLDP TLV to endpoint device (ED) like IP Phone first (1), to get its device type and capabilities information, then it will receive that information in LLDP-MED TLV back from endpoint devices (2), after that the network connectivity devices will transmit LLDP-MED TLV (3) to provision the endpoint device to such that the endpoint device's network policy and location identification information is updated. Since LLDPDU updates status and configuration information periodically, network managers may check the result of provision via remote status. The remote status is updated by receiving LLDP-MED TLVs from endpoint devices. GS1920 Series User's Guide 251

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Chapter 32 Link Layer Discovery Protocol (LLDP)
GS1920 Series User’s Guide
251
Figure 183
LLDP Overview
32.2
LLDP-MED Overview
LLDP-MED (Link Layer Discovery Protocol for Media Endpoint Devices)
is an extension to the
standard LLDP developed by the Telecommunications Industry Association (TIA) TR-41.4
subcommittee which defines the enhanced discovery capabilities, such as VoIP applications, to
enable network administrators manage their network topology application more efficiently. Unlike
the traditional LLDP, which has some limitations when handling multiple application devices, the
LLDP-MED offers display of accurate physical topology, interoperability of devices, and easy trouble
shooting for misconfigured IP addresses. There are three classes of endpoint devices that the LLDP-
MED supports:
Class I: IP Communications Controllers or other communication related servers
Class II: Voice Gateways, Conference Bridges or Media Servers
Class III: IP-Phones, PC-based Softphones, End user Communication Appliances supporting IP
Media
The following figure shows that with the LLDP-MED, network connectivity devices (NCD) like
Switches and Routers will transmit LLDP TLV to endpoint device (ED) like IP Phone first (1), to get
its device type and capabilities information, then it will receive that information in LLDP-MED TLV
back from endpoint devices (2), after that the network connectivity devices will transmit LLDP-MED
TLV (3) to provision the endpoint device to such that the endpoint device’s network policy and
location identification information is updated. Since LLDPDU updates status and configuration
information periodically, network managers may check the result of provision via remote status.
The remote status is updated by receiving LLDP-MED TLVs from endpoint devices.