Concerns Over Increased 802.11n Power Usage

alphadogg writes "Next-generation 802.11n systems promise to considerably improve WLAN performance. But the processing required for the boost sucks up more power than the older 802.11a/b/g networks. Still, many enterprise-class Wi-Fi vendors claim to deliver full 802.11n capabilities without enterprise customers having to touch their power infrastructures. So what gives?"

Comments

Re:What about the remote clients?

[maird]

Maybe skimming TFA wasn't the best basis for comment. The article mentions no power issue at the client. It's basically saying that:

• The problem applies to 802.11n wireless access points powered via Ethernet (PoE)
• The 802.3af PoE standard only permits about 12.95W of power at the cable end where power is required
• 802.11n devices in current production typically require up to 18W
• 18 > 12.95
• Therefore, such 802.11n access points cannot operate at full power (probably limiting their transmit power)
• Therefore, such 802.11n access points cannot transmit with the same range as a fully powered version
• Clients are unaffected and can transmit at full power and full range (maybe the AP can't reach them to reply though)
• The 802.3at PoE standard (when available) will provide up to 30W for devices

Summary is misleading

[russotto]

First of all, this has little to do with what is usually considered power infrastructure. This has to do with power-over-ethernet. It appears some dual band 802.11n radios require more power than one particular specification (802.3af) allows. Solution? Don't use 802.3af, or, don't use the radios which require too much power. Not really a big deal. I expect that manufacturers will bring the power requirements down to allowable levels over time.

Re:Not a significant usage of power

[evilviper]

It's like 8 watts instead of 3 watts

From TFA: "some 802.11n Draft 2.0-based access points consume up to 18 watts."

That's why you don't need to upgrade your infrastructure.

From TFA: "802.3af power-over-Ethernet (PoE) switches and power injectors supply about 15 watts of power at the switch port."

No go sit in the corner and think about what you've done...

Re:What Gives? Simple.

[seanadams.com]

Enterprise hardware does not use general-purpose CPUs, it uses special-purpose ASICs

Actually they don't - take a look in a high-end AP some time. "Enterprise" wireless systems use the same, or often older generation, of wireless technology that is in consumer access points. Competition in the consumer AP market is what drives all the incredible price/performance in wireless technology, and I assure you nobody is going to spend the tens of millions to do a custom spin of one of those chipsets for the relatively small high-end market. Those products sell on branding, special software features, and support contracts, not silicon performance. And as far as the CPU/memory etc, these are going to be much LESS specialized in a high-end system than in a consumer AP. Low-cost APs use highly integrated ARM or MIPs-based SOCs that are designed for sub $20 BOM cost. A higher-end system, however, is not bound by BOM costs and might have four times the memory and a more general purpose processor capable of running more software.

Routers and switches are a different story, and those DO use ASICs and FPGAs. The high-end models of these have to deliver a totally different hardware feature set than consumer equipment, and unlike wireless technology, the bleeding edge tends to be developed for the highest priced products before trickling down.