Tag Archive for 802.3at

| April 9, 2015
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802.3bt More Power to the People’s Devices

802.3bt More Power to the People's DevicesPower over Ethernet (PoE) powers more than one million end devices today. To continue PoE’s success, the IEEE is answering the market’s demands for more power by developing 802.3bt the third generation of PoE.

The first generation of PoE (2003), 802.3af delivered 12.95 Watts. The second generation, 802.3at (2009) provides 25.5 Watts to the equipment. The new version of PoE will address the need for higher-power PoE. The IEEE has proposed a new standard, 802.3bt, which promises to double the power output of the current 802.3at standard. The new 802.3bt standard, scheduled to be released in 2017, will also adjust PoE to work with 10Gbase-T.

IEEE logoCabling Installation & Maintenance Magazine provides an excellent overview of the new standard. They report that the IEEE 802 LAN/MAN Standards Committee which develops and maintains networking standards like Ethernet, VLANs, and Wireless LAN, is developing the new standard. The DTE Power via MDI over 4-Pair Task Force is working to specify a set of next-generation PoE specifications, and the levels of power likely to be delivered ultimately via the 802.3bt standard will still work on twisted-pair cable, possibly as a four-pair PoE specification which could improve energy efficiency and offer greater power.

New POE Applications

IndustryApplicationTypical Power Consumption
HealthcareNurse call system30-50W
RetailPoint of sale system30-60W
BankingIP Turrets45W
Building ManagementVariable air volume controllers, Access controllers40-50W
Enterprise ITThin clients, Virtual desktop terminals50W
HospitalityPOE switches45-60W
Premise SecurityPTZ cameras30-60W
IndustrialBrushless drives, Motor control>30W
VariousDigital signage>30W
VariousMultichannel wireless access points>30W
via CommScope

The new PoE standard will support 10GBase-T. The 10GBase-T standard uses all 4 pairs to send data. These facts will force the IEEE 802.3bt committee to figure out how to keep the power from interfering with the data on the same wires to supply a minimum of 49 watts at the powered device. One of the key parameters the article mentions is to limit pair-to-pair current imbalance.

POE logoOther goals for the 802.3bt standard are: to be backward-compatible with “af” and “at.” and increased energy efficiency. According to the article, a global move to 4-pair POE systems would create potential energy savings of 60.8 million kilowatt-hours which would prevent greenhouse gasses from 66 million pounds of coal saved annually.

Paul Vanderlaan, technical manager of cable maker Berk-Tek – Nexans’ advanced design and applications lab and other cabling-industry technical experts believe that 802.3bt’s support of 10GBase-T means that the minimum twisted-pair cabling system requirement will increase.  In order to support 10GBase-T, it seems likely that a Category 6A system will be the recommendation. The author notes that the IEEE does not address cabling performance, that is the focus of groups like the TIA or ISO/IEC.

The transition to the new PoE standard will not be simple. CommScope published a white paper where they explain:

Category 6A cabling… Category 5e cabling only provides the minimum level of performance required. Therefore, it is recommended to use Category 6 or Category 6A cabling-preferably solutions … 

Berk-Tek’s Vanderlaan explained why Category 6A cabling is the preferred system. He summarizes the electrical-engineering calculations;

As a general rule, increased copper content, or larger gauge size, will aid in power delivery … when you migrate … you should see larger gauge sizes and more copper content.

system performance characteristicsUnder the new standard users will have to pay attention to new cabling-system performance characteristics like DC resistance unbalance and pair-to-pair resistance imbalance.  The higher wattage’s up to 1 full amp (1,00 milliamps) will present challenges to performance requirements. Mr. Vanderlaan told Cabling Installation & Maintenance Magazine:

For users, cable selection will be based not just on the speed that can be supported, but rather on speed as well as power delivery. What you simply plug in today, you may want to also power in the future.

A new challenge cable plant owners will have to consider is heat. CommScope explains that heat generated within bundles of cables supporting IEEE 802.3bt could rise enough to effect performance.

ambient temperature… the temperature of the cabling will rise due to heat generation in the copper conductors  … the temperature of the cable bundle higher than the ambient temperature of the surrounding environment … The IEEE 802.3bt four-pair PoE standard is expected to assume a maximum temperature rise of 10 degrees Celsius (50 degrees F) when all four pairs are energized … the ambient temperature should not exceed 50 degrees Celsius (122 degrees F) … CommScope recommends Category 6A cabling for four-pair PoE applications. Because increased thermal loading can also increase insertion loss, the maximum cable length should be de-rated for higher temperatures, per ANSI/TIA-568-C.2.

Several vendors have already released pre-standard device-powering systems to meet users’ current needs.

As in the pre-PoE standard days, Cisco (CSCO) has marketed proprietary PoE systems since 2011. Cisco’s Universal Power Over Ethernet (UPOE) technology, which delivers 60 watts of power to devices powered by the Catalyst 4500E; some of those devices include Cisco IP phones, personal telepresence systems, compact switches and wireless access points.

Also, the non-standard Power Over HDBase-T (POH) was introduced by the HDBase-T Alliance a trade group that promotes and standardizes HDBase-T technology for whole-home distribution of uncompressed high-definition (HD) multimedia content. This system delivers up to 100 watts of power to TVs and other devices over distances up to 100 meters/320 feet via one Category 5e or 6 cable with standard RJ45 connectors.

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The new standard is a welcome addition to the toolkit. Cost savings is one of the appeals to PoE. On many projects, PoE low voltage contractors can do the work rather than electrical contractors. If the new system pushes the maximum rate to 75W at the devices as some predict, with there be a backlash from the EC’s and authorities having jurisdiction? Time will tell.

In the meantime, the article says owners and managers should check their current infrastructure with eyes toward how the next generation of devices might be powered via more-capable PoE technology.

Of course, it is always a good idea to pull out your acceptance documentation to understand the installed base of the cable and the likelihood that the cable has the electrical performance characteristics required to support the next generation of PoE.

Related articles

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

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| November 7, 2013
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802.11ac Wi-Fi – Don’t Bother Yet

802.11ac Wi-Fi - Don't Bother YetThe new iPads are here! The new iPads are here! There’s no 802.11ac here! But that’s expected. Experienced Apple watchers know that Apple likes to let new radio technologies mature before they integrate them into their new idevices. So that means most enterprises can slow their plans to upgrade their Wi-Fi to the new standard according to Kevin Fitchard at GigaOM.

The new iPads are hereThe latest Apple (AAPL) tablet doesn’t sport the new soon-to-be-completed IEEE 802.11ac standard, even though Apple’s latest generation routers, PCs, and laptops all support it. GigaOM reports Apple is providing is a speed boost to the now thoroughly established 802.11n networking standard in the form of multiple-input multiple-output (MIMO) smart antenna technology. Like many Wi-Fi routers on the market, the iPad Air has dual antennas, allowing it to wend two parallel paths over the unlicensed airwaves. The MIMO implementation will double the speeds at which the iPad can access Wi-Fi networks, according to Apple.

The Wi-Fi Alliance only began certifying commercial 802.11ac devices in June, and even those devices only incorporate partial versions of the full 802.11ac spec. The IEEE isn’t expected to fully complete the standard until 2014. Very few smartphones and tablets have ac embedded as of yet, though the technology is making its way into consumer and enterprise routers and PCs, including Apple’s newest MacBooks and iMacs.

iPad AirBut waiting another year for 802.11ac-enabled iPhones and iPads also means we’ll probably have to wait another year before we see wide-scale adoption of the standard in public hotspots and access points. Unlike in the home, most outdoor and public Wi-Fi connections are made over mobile devices, not PCs.

In an interview with GigaOM, Boingo VP of corporate communications Christian Gunning said it hasn’t turned up 802.11ac in any of its hundreds of thousands of owned and managed hotspots yet, simply because it’s seeing very few devices with ac radios trying to access its network.

higher-powered 802.3at Power over EthernetFierceCIO‘s Paul Mah offers more reasons to delay the roll-out of 802.11ac. The advanced 802.11ac radio is more power-hungry than earlier iterations of Wi-Fi. So it will more likely need the use of the higher-powered 802.3at Power over Ethernet (PoE) to run 802.11ac with all its bells and whistles. It is possible that businesses still on 802.3af PoE (rb- Majority) may well have to incur extra infrastructure costs to deploy 802.11ac today. Mr. Mah contends that it is yet to be seen if improved 802.11ac chipsets will allow firms to stick with legacy PoE. (rb- For a refresher on PoE, check out these posts 802.3af and 802.3at)

Another consideration according to FierceCIO is clients. The handful of business-grade 802.11ac wireless APs on the market today typically support three spatial streams, which allows for a (theoretical) maximum data rate of 1.3Gbps in the 5GHz band. Though this is a significant improvement over 450 Mbps 802.11n, the dearth of 802.11ac client devices renders this a moot point. Some will argue that Apple did incorporate 802.11ac into the new MacBook Air laptops.  However, they did not include it in the new iPads, or the iPhone 5S and iPhone 5C smartphones. And with no smartphones or tablets equipped with 802.11ac capabilities today, this does make deploying it a rather pointless strategy for BYOD.

802.11ac "second wave"Finally, Mr. Mah points out that while 1.3Gbps is a good speed to have, we should keep in mind that 802.11ac does have a theoretical maximum speed of 7 Gbps. A “second wave” of 802.11ac that implements four or more data streams for much faster speeds should be arriving in the second half of 2014. He says current signs are that this second wave of 802.11ac devices might need new processor chips–which means you will have to buy new 802.11ac hardware to benefit.

GigaOM’s Fitchard stresses Apple’s influence when it comes to popularizing new technology, he says the iPhone and the iPad’s reach shouldn’t be underestimated. As an example, new Passpoint-certified phones have been out for more than a year, but it wasn’t until Apple started offering support for Passpoint’s automatic login technology in iOS7 that the wireless industry took notice. It was only after Apple made iOS7 publicly available, that Boingo started Passpoint trials.

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I’m not saying 802.11ac is a bad thing, but enterprises need to ignore the hype cycle and make decisions that are best for them and not the multi-billion dollar networking industry. IMHO 802.11ac is still immature, there are few devices out there that can fully take advantage, the full feature set is not fully implemented in silicon and you finished the upgrade to 802.11n yet?

What to do?

What does your wired network look like? Are you still connecting your AP’s at 100 Mbps? That is a bottleneck with 802.11n.

Do you have enough juice? What is your PoE status? Do you have enough PoE+ ports? Are they being used for just an access port – wasting the extra costs of a PoE port?

Both switches cost money, is there a budget available for these items or is IT going to spend an operational budget to address a structural issue?

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

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| September 12, 2013
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PoE Overworked

PoE OverworkedGary Audin at No Jitter warns that Power over Ethernet (PoE) is not always a plug-and-play environment and PoE should be monitored, managed, and efficient. In this article, Mr. Audin observes that PoE has evolved into an electrical power device utility platform. POE started out as a centralized power source for IP phones, backed up with an Uninterruptible Power Supply (UPS). (rb- Click here and here for my overview of PoE) Since those early Cisco dominated days. The article says PoE now is called upon to support wireless access points; environmental controls; point, tilt, and zoom cameras; lighting control; clocks; door controls; Bluetooth devices; RFID; now laptops, and still more to come.

The LAN switch is the PoE source, but the article warns it can be overwhelmed with the power drain, which produces headaches for IT. Unless properly managed, the PoE function can experience:

  • power drainA blown-out power supply. Smoke is an indicator of this condition.
  • Reduced power to all devices with degraded service from all the attached devices.
  • An added PoE device does not work.
  • The more power is drawn by PoE, the shorter the UPS battery life. The original UPS design could last 20 minutes. Added PoE devices could shorten this to 3 minutes.

PoE IP phones and other devices can signal to the PoE network what class of device it belongs to and how much power it may need. Class 0 devices, usually older devices, do not indicate their PoE power requirements. These devices may draw any power level from none to maximum. The other standard classes, 1-3, range from very low power to mid-level power consumption.

Class 4 is a newer class of device requiring PoE+ (802.1at) and needs to draw more than the 12.95 Watt maximum provided by the original standard PoE. Class 4 devices must be powered by PoE+ ports and may not function correctly on an 802.3af PoE port. Most IP phones are in class 2. IP phones with color screens and other advanced features may be categorized as class 3 devices.

PoE classes

PoE Access Points Wireless LAN access points are also common PoE devices, many of which started out as class 2 and 3 devices. As the wireless speeds increased, so did the power requirements. The 802.11ac standard means that the access points (AP) will have a 1 Gbps connection back to the switches and routers.

site-surveyAt issue is the PoE required. It is likely that each AP could need 20 to 30 watts, the limit that the 802.1at PoE+ standard delivers. Many installed switches cannot support PoE+. So the enterprise has to buy new switches or power supplies or power injectors. (rb- add this to your site-survey when you plan to implement 802.11ac)

Mr. Audin spoke to Tim Titus, CTO, and founder of PathSolutions, (they happen to sell a network management tool) about what he considers a good approach to monitoring and managing POE. He told No Jitter,

“Regardless of whether there are any PoE or PoE+ devices on a network, it can be very helpful to monitor the health of our network equipment’s power supplies. The best monitoring system watches the status and power consumption of each power supply, what percentage of utilization it is running, and which interfaces are drawing power, so power policing can be achieved.”

He provided this example of missing power management.

“Keeping an eye on power supplies avoids unpleasant discoveries. One unlucky network administrator had two power supplies installed in a network chassis (one primary and one backup). Unfortunately, when the primary power supply stopped working, nobody knew, since the backup power supply was doing its job of keeping everything running. The problem wasn’t noticed for over six months. Nobody was in the empty remote wiring closet to notice the lack of lights on the power supply. The users remained blissfully unaware of impending doom until the wee hours of a weekend when the second power supply was shut off by a circuit-breaker trip!” 

Mr. Titus pointed out to Mr. Audin, that monitoring should happen at the port level,

“Not only will a monitoring system show you what mode a PoE port is operating in, but it should also provide a view of relevant error counters.

  • MPS Absent and Invalid Signature errors frequently point to broken or defective powered devices.
  • Overload conditions and short-circuits typically point to wiring problems (or somebody re-wiring devices in use).
  • Denied errors can point to devices asking for more power than the switch has available, and may indicate that it is time to consider adding another power supply to a large Ethernet chassis.”

How did that happen?

Finally, many network engineers try to buy limited PoE due to the cost premium of POE ports, only to find that half of their PoE ports are used by non-PoE devices such as PCs. With a monitoring tool, the engineers could have avoided buying expensive PoE ports or purchased less expensive “ordinary” Ethernet ports.  The engineers should have an up-to-date PoE port inventory and use it to avoid over-buying the PoE by playing safe in their design. (rb- Been there done that, I’ve been in many customer’s closets and found POE switches full of PC and printer access ports.)

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The author warns not to assume that PoE is always a plug-and-play environment. PoE should be handled like a utility–monitored, managed, and efficient.

I have tried to build custom fields by working with reports in SolarWind’s Orion by working with MIBs, it’s not the funnest thing in the world. I wonder if this product does a better job.

Related articles

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

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| July 12, 2012
2 comments

Power Over Ethernet 802.3at

Power Over Ethernet 802.3atA client recently asked what happened to the network design rule of thumb which said do not install data cables anywhere near electrical cables? The fear of cross-talk, interference, and corruption of the data traffic seems to have disappeared with power over Ethernet. He rightly pointed out that now it seems OK to mix data and power in the same cable going to a networked device. Power over Ethernet (PoE) is similar in principle to the way that the copper wire pair that carries your POTS (Plain Old Telephone System) telephone signals into your house also carries enough electricity (48v DC) from the telco Central Office to power the phone’s core elements of the headset, dial, and ringer. The latest PoE standard is 802.3at.

See part 1 here.

can cut installation costsPoE end devices (PD) became popular with the bean-counters because these devices can cut installation costs by as much as 90% over traditional powering techniques. With cost savings comes demands for new products however, the power limitation of 802.3af  prevented full support of  “high power” devices via the industry-standard PoE. In September 2005, the IEEE launched a task force to begin reviewing new PoE specifications to enhance the IEEE 802.3af guidelines into a next-generation standard.

The IEEE ratified the new PoE standard in 2009 called IEEE 802.3at-2009 PoE standard (aka PoE+ or PoE plus). Under the new standard Power Sourcing Equipment (PSE) must provide at least 30.0 Watts at the PSE port and 25.5 watts continuous power to up to 100 meters from the PSE over Cat5e or better cable to each PD. This will allow PoE to address applications such as multi-radio wireless APs, Pan-Tilt-Zoom (PTZ) gimbal-mounted cameras, 802.16 subscriber stations, 3G/LTE femtocells, perimeter security equipment, videoconferencing products, thin clients, and even some notebooks, as well as emerging applications. The new standard also provides full backward compatibility and interoperability to existing 802.3af compliant PSE’s and PD’s.

802.11n Wi-Fi technologyThe widespread use of 802.11n Wi-Fi technology has been one of 802.3at’s drivers. The multiple-input/multiple-output (MIMO) architecture used by 802.11n technology requires more power than earlier technologies, like 802.11a and 802.11b/g.

Installation practices and cable type impact the ability to use PoE+ to power a PD. Installation practices are outside the scope of the IEEE 802.3at standard. The Telecommunications Industry Association (TIA) has addressed these issues in a Telecommunications Systems Bulletin (TSB). TSB-184, Guidelines for Supporting Power Delivery Over Balanced Twisted-Pair Cabling describes how the impact of environmental conditions of the installed cabling and heat dissipation profiles of the cables’ effect the telecommunications cabling capacity to support the PoE+ application.

But Wait There’s More

IEEE logoOne of the most important benefits of the IEEE 802.3at standard is it incorporates existing 802.3af PoE safety requirements. The new standard includes compliance detection features for safe powering as well as safe PD disconnection in overload, short-circuit or under-load conditions enabling fast and safe adoption of the new standard.

The definition of a powered device changed under the IEEE 802.3at-2009 standard. The new standard considers the PD to be the powered interface, as opposed to the entire device being powered. This means that one device can have two power interfaces, each taking 25.5W, inside the same box. Nothing precludes these to be connected—one over the two pairs using lines 1, 2, 3, and 6 and the other over the two pairs using lines 4, 5, 7, and 8. This is what makes it possible to double the standard 802.3at-2009 maximum of 25W and go up to 51W while fully complying with the standard. Applications that need 51W PoE are an exterior IP camera with a heater or an access control system that includes a controller, a reader, and a few door locks which can easily consume 45W of power or more.

POE PTZ cameraAnother way PoE system developers are addressing the growing device powering requirements is by employing the option in the IEEE standard to add PoE functionality over all four pairs of the Ethernet cable. This option opens the door for safely delivering 60 watts of direct current (DC) power over a single Ethernet cable, using current levels of 600 milliamps (mA) than the 1.2 Amp level of two-pair 60W midspans.

The manufacturers claim this configuration can cut power consumption by 15% compared to two-pair solutions. This could translate into savings of about $25 per year per powered device, assuming energy costs of $0.10 per kilowatt-hour.

Related articles
  • IEEE Introduces Groundbreaking Standard for Body Area Networking (sys-con.com)

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

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