Mushrooming PoE use cries out for true standardization
More and more devices, such as Wi-Fi access points, Internet Protocol (IP) phones, security cameras, and LED lighting, are leveraging Power over Ethernet (PoE) for low-voltage DC power. And PoE’s application space is poised to explode beyond the information technology (IT) domain with the proliferation of the Internet of Things (IoT).
Indeed, there is already considerable confusion about what exactly the term “PoE” means. It isn’t so much that the technological concept itself—enabling delivery of power via the same cables that provide Ethernet—is especially complex to grasp. “PoE” has organically emerged as the generic term for equipment that is designed to comply with the IEEE Ethernet Standard, 802.3-2015, Clause 33,“Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI),” even though the term does not show up in the standard document other than as a searchable keyword. Because nobody owns the term, and because a range of standardized, non-standardized, and somewhat-standardized implementations are available in the market, “PoE” means a lot of different things to a lot of different people.
The Ethernet Alliance, as a global, non-profit industry consortium dedicated to the continued success and advancement of Ethernet technologies, is seeking to minimize that confusion. Their PoE Certification Program is intended to enable users to easily differentiate between standards-based and proprietary PoE solutions by validating interoperability among IEEE 802.3-based ones. By helping users easily identify interoperable products via a credible registry list of providers, the Ethernet Alliance program is intended to improve the PoE user experience.
Take a look at the online comments forums, and you will quickly understand the confusion and guilt by association that non-standardized PoE products are introducing into the entire Ethernet ecosystem.
There are manufacturers offering products designed to portions of IEEE 802.3 PoE, but which do not fully implement the standard. In these cases, the product might appear to interoperate sufficiently to function—but perhaps not fully, or at lesser performance quality than advertised.
Then there are products available that deliver power over cabling used for Ethernet but not designed to IEEE 802.3. These products might be labeled as “PoE” and/or “compatible” with standards. As such, they might bypass detection or current limiting or other important protections in IEEE 802.3, they may use different voltages, or exhibit other basic differences.
As a result, the PoE market is already confused, just as IoT proliferation is illuminating PoE’s phenomenal application potential.
Participation in the Ethernet Alliance PoE Certification Program is easy:
- The vendor fills out a Certificate Mark License Agreement (CMLA) and certification application for PoE solutions as currently defined in IEEE 802.3.
- Member companies can pursue testing at the University of New Hampshire InterOperability Laboratory (UNH-IOL), or perform testing themselves using commercially available equipment that is approved by the Ethernet Alliance.
- The Ethernet Alliance awards program logos for products successfully completing testing. The logo indicates whether the product is power sourcing equipment (PSE) or a powered device (PD). PSE include devices which can inject power onto Ethernet lines, such as Ethernet switches or mid-span power injectors. The PD category encompasses most any device with an Ethernet port (wireless access points, network bridges, small Ethernet switches, internet phones, cameras, terminals, digital signs, sensors, access controls and monitoring, lighting, home/office automation systems, etc.) The logo also shows the product’s highest power classification.
- Conforming products are added to the Ethernet Alliance PoE Certification Program integrators registry list online, and vendors can stamp those products with the Ethernet Alliance logo.
The program is open to Ethernet Alliance members and non-members alike, and certification may be at either the system or component level.
Figure 1 If the classification number in the EA CERTIFIED logo for a PSE is greater than or equal to the PD classification number, the user is assured the PSE will fully power the PD.
Win-win for manufacturers & users
The Ethernet Alliance logo will help users focus in on PoE products that are both standards-based, and provide the performance and interoperability required.
Certification benefits for participants are clear and tangible: fewer interoperability issues, happier customers, and reduced support costs. Plus, it will help participants more efficiently connect with potential partners, and deliver more comprehensive, end-to-end solutions to customers.
PoE certification is a clear market need, as evidenced by the considerable interest in the Ethernet Alliance PoE Certification Program shown across the expanding Ethernet ecosystem: Ethernet Alliance members in this program already make up 90% of today’s PSE switching industry.
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— David Tremblay chairs the PoE Subcommittee within the Ethernet Alliance, and is a system architect at Hewlett Packard Enterprise.
—Chad Jones is Technical Leader at Cisco Systems and an Ethernet Alliance member.