Siemens claims 802.11n power problem cracked
- 24 January, 2008 12:10
Siemens is launching a wireless LAN system that it claims can run full 802.11n on normal power over Ethernet, but refuses to divulge how it has managed a trick that is beyond other players including Cisco.
"We have two concurrent radios, both running 3x3 MIMO with all the features, including channel bonding, running at just over 12W," said Luc Roy, vice president of product planning at Siemens. If true, this claim means the new HiPath AP3610 / AP3620 access points can run 802.11n fast Wi-Fi, at full speed, on two radios, at 2.4GHz and 5GHz simultaneously, using conventional Power over Ethernet installations without a costly upgrade.
However, all other enterprise Wi-Fi vendors agree that, at present, two 802.11n radios require around 15W, which is more than can be delivered over the IEEE 802.3af standard for powered Ethernet, which can't go above 12.95W. They have come up with various workarounds, including using fewer antennas or using shorter cables to the APs (Aruba), using two Ethernet cables to take the power (Trapeze), using proprietary PoE (Cisco), or using 802.11g on the 2.4GHz band (Colubris).
Roy dismissed these approaches, but would give only a very vague explanation of how Siemens had succeeded where the rest of the industry has failed, although the company uses the same Atheros silicon used by all the other vendors except Cisco.
"Some of this is our own intellectual property," he said. "We leverage the Atheros radio reference design - the componentry and board layout is where everything is changed." The changes were "common sense," he added, making some areas more optimized and efficient.
The access points will be available in March, costing a‚¬963 (US$1,878), and require only a software update to Siemens existing wireless controllers - which also updates Siemens' HiGuard intrusion detection and security software to handle threats including rogue 802.11n access points. Users may need to upgrade connections to Gigabit Ethernet, but this will only be required as traffic levels ramp up, said Roy.
Siemens does not need to launch a new controller to support 802.11n, said Roy, because it has a distributed architecture, which delegates many decisions to the access points, and avoids bottlenecks by not channelling all traffic through the controller. "Managed traffic, such as voice and so on is definitely tunnelled to the controller," said Roy. "This gives seamless roaming from one subnet to another."
This "locally bridged architecture," comes from respected Wi-Fi startup Chantry, which had a voice-centric Wi-Fi system, and was bought by Siemens in 2004. It is similar to the distributed architecture adopted more recently by Trapeze and Colubris, acknowledged Roy.
The Chantry heritage could lend credibility to Siemens' claims to any kind of Wi-Fi leadership: although little has been heard of it since Siemens acquired it, the company has been nurturing Chantry's Wi-Fi internally, and has built up a substantial market share, largely based on sales to Siemens' PBX customers, said Roy.
"In Europe we have more than five percent market share in Europe," he said. "It's not far from 10 percent." Analysts can't verify that, however, as Siemens, like Trapeze does not share figures with them. So far, its market is predominantly in Europe, but it has doubled its revenue every quarter in Europe, Roy boasted.