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Independent Analyst Confirms Siemens’ PoE 802.11n Claims

Test results by Craig Mathias of Farpoint Group verify that the HiPath Wireless Access Points (APs) recently announced by Siemens Communications, deliver dual-radio, 3x3 MIMO 802.11n functionality while remaining compliant with the wattage limitations of industry-standard 802.3af Power-over-Ethernet (PoE). Farpoint Group confirmed this innovative capability in just-published results of comprehensive lab testing of the Siemens HiPath Wireless AP3620. Siemens also announces that its new 802.11n HiPath Wireless AP has received the Wi-Fi CERTIFIED seal of approval for 802.11n draft 2.0 from the Wi-Fi Alliance .

The HiPath Wireless AP3620 was awarded the certification after successfully passing a rigorous sequence of qualification testing, which ensures the compatibility of WLAN products based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11n WLAN specifications. The HiPath Wireless AP is certified for adhering to industry standard tests for interoperability, the latest in security protection, and backward compatibility with previous generations of Wi-Fi gear.

Farpoint Group performed its own tests aimed to verify if Siemens had met the difficult challenge of addressing both the physical power delivery constraints of the IEEE 802.3af PoE and the needs of power-hungry, dual-radio 802.11n APs. The 3x3 MIMO technology at the heart of 802.11n relies on the use of six transmitter/receivers (three for each radio) – compared with just two for 802.11a/b/g APs. Depending on the implementation, this additional hardware could consume significantly more power than the 12.95 Watts that 802.3af PoE is designed to deliver across a 100-meter Ethernet cable. Many other WLAN vendors have introduced 802.11n solutions with workarounds to address this problem, which underscores the significance of Siemens' achievement.

"We were skeptical of Siemens' claim that .3af power would be sufficient for dual-radio, 3x3 MIMO operation", said Craig Mathias, a Principal with Farpoint Group and author of its published Technical Note. "It's ferociously difficult from an engineering standpoint, so we jumped at the chance to verify Siemens' claims."

Details of Farpoint Group's lab tests are available in its published Technical Note (Document FPG 2008-61.1, February 2008), entitled 802.11n Access Points and Power over Ethernet: Key Considerations. Mathias tested the HiPath Wireless 802.11n solution within a test network environment that consisted of both integral and add-on .11n clients, PoE switching infrastructure, and benchmarking software. "We saw outstanding performance with both radios running simultaneously at expected 3x3 MIMO throughput levels", Mathias said. Tested throughputs ran as high as 143 Mbps – far faster than the typical 25 Mbps maximums of 802.11a/b/g wireless standards. This all took place while the AP drew power across 100m Ethernet cables connected to 802.3af PoE switch ports or .3af-compliant power injectors.

"The test results prove that Siemens has clearly achieved the feat of providing full dual-radio 3x3 MIMO 802.11n while being powered by 802.3af PoE", Mathias said. "This accomplishment is clearly very difficult, and we expect Siemens to gain some real market advantage from this for some time."

The Siemens HiPath Wireless APs' compliance with the PoE 802.3af standard makes installation of 802.11n AP deployments much simpler and much more economical than competing approaches. HiPath Wireless APs only need to be plugged in to existing PoE-enabled Ethernet ports, while other 802.11n solutions could require pulling AC power, additional Ethernet cables, or adding completely new PoE infrastructure like switches or port injectors – all of which are costly and time-consuming.

"We chose Siemens' HiPath Wireless 802.11n solution because it is ready to deploy now, offers great advantages in how it deals with the PoE issue, and is easy to install", said Sam Brown, Director of IT Services for the Georgia World Congress Center, a 3.9 million square foot conference, entertainment, and sports venue. "After upgrading the software on our HiPath Controller and doing a few quick configuration changes, all we had to do was unplug our old HiPath Wireless Access Points and plug in the new ones. We were even able to use the same mounting bracket. In all, it took us less than 30 minutes to light up our trial area with 802.11n."

Siemens' PoE implementation works alongside its unique Virtual Network Services (VNS) architecture – which optimises 802.11n traffic flow and enables enterprises to deploy 802.11n without upgrading central network infrastructure and controllers.

"While 802.11n delivers the higher speed and improved range customers want, the cost and complexity of enabling an existing network to handle 802.11n has held many enterprises back", said Luc Roy, Vice President of Enterprise Mobility for Siemens. "HiPath Wireless makes it possible to easily deploy reliable, high-speed 802.11n with minimal changes to your existing network. And with the Wi-Fi Alliance certification, users can be assured of Siemens' further commitment to providing best-of-breed solutions that add true value to the enterprise."

Siemens' HiPath Wireless solution will begin shipping in March 2008.



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