IEEE 802.3at LLDP Dynamic Power Management – An Intelligent Powering Mechanism for Enhanced Large-Scale High-End Critical Video and PoE Applications!

With the latest technological developments and the modernization of network infrastructures, today high-end IP cameras, VoIP and video are becoming a popular solution for communication and monitoring in industrial highly critical PoE surveillance applications. Implementing an intelligent powering mechanism in these networks becomes of even a higher importance for network administrators.

Some of legacy PD devices feature user defined manual mode and forced powering mode to support non-standard PD devices without PoE signature resistor for applying in different networking systems. However, these mechanisms just help enabling the non standard PoE. As network managers begin to take a more refined, granular approach to powering the network, the role of the new powering mechanism becomes more important.
In this regard, Korenix JetPoE series implement the Link Layer Discovery Protocol (LLDP) of IEEE 802.3at High Power PoE into its latest PoE systems for intelligent power budget negotiation between PD devices.

Enhancement of LLDP – the IEEE802.3at LLDP
The new LLDP standard has been created by the Telecommunications Industry Association (TIA) to fit the need of multi-vendor High-power PoE and VoIP deployments. Compared to the 802.3af Physical Layer Classification mechanism, the new 802.3at LLDP designates Physical layer classification + Data Link Layer.
As a result, it allows for Media Endpoint Devices, such as VoIP phones, to exchange basic and advanced configuration information, including Power over Ethernet management. The new 802.3at LLDP is considered to be an important way for the network to keep track of endpoints and treat different endpoints in appropriate ways depending on what the endpoint is and does.

Benefits of implementing 802.3at LLDP PoE Classification of Korenix JetPoE series
The new standard along with the IEEE 802.3at provide some enhancements to the advanced PoE management capabilities of Korenix new High Power PoE switches. The LLDP packet of the Korenix high power PoE switches provides smart power budget control behavior to fulfill the needs of higher end setups requiring flexible power delivery.

Under the 802.3af PoE standard, a PoE source can deliver fixed power to the device using the limited physical layer power classification. As mentioned previously, rather than using the 802.3af standard, the IEEE 802.3at specification mandates that all PDs also support dynamic power management mechanism - a more flexible Layer 2 power classification method based on Link Layer Discovery Protocol (LLDP). The use of LLDP for power classification provides “fine grain” PoE power allocation of 0.1 watt granularity, along with the ability to dynamically reallocate power.

By using the ongoing dynamic re-negotiation of the 802.3at LLDP PoE, the PD devices can perform more intelligently. So if the PD device requests for 10W power in the first stage, the PSE will apply the 10W power. Later, if the PD needs higher power, such as 25W to power up high-end cameras or VoIP phones, the PSE will reply the request of the PD by sending back 25W power.

The result is that it improves power allocation and management between the PSE and PD allowing the devices to negotiate dynamically and provide more flexibility to customers.

3rd Party PSE Conformance Tested

Korenix switches, which support 802.3at High Power PoE by the LLDP PoE classification, are:

• JetNet 5710G series Industrial 8+ 2G Managed High Power 802.3at PoE Switch
• JetNet 6710G series Industrial 8+ 2G Managed M12/RJ45 High Power 802.3at PoE Switch
• JetNet 5728G series Industrial Rackmount 24+4G Managed High Power 802.3at PoE Switch

[To inquire for more information, please contact Korenix Sales]