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Wireless networking heads into fourth generation -- but should you follow?

For enterprises seeking to move their Wi-Fi access from best-effort to mission-critical, so-called fourth-generation implementations, from such companies as Meru and Extricom, have been making inroads and could offer more consistent wireless access.

For enterprises seeking to move their Wi-Fi access from best-effort to mission-critical, so-called fourth-generation implementations, from such companies as Meru and Extricom, have been making inroads and could offer more consistent wireless access.

"I think from a deployment standpoint … fourth generation makes a lot of sense to me, particularly from very dense environments," said Michael King, research director at Gartner. "It makes even more sense in the .11n side of the world."

That is because 802.11n, the upcoming standard for wireless access, will allow greater throughput and range, as well as some more business-minded features (including tightened security), raising the possibility that some enterprises will ditch Ethernet entirely for an almost completely wireless LAN.

So what exactly is fourth-generation Wi-Fi? Today, most wireless access points (APs) are carefully placed to create circles of slightly overlapping Wi-Fi coverage, each on a different frequency channel. This means that each time a laptop moves from one room to another, for example, the wireless connection must be momentarily broken and rebuilt on the client end.

King noted, however, that improvements in third-generation technology made these AP handoffs minimal enough almost not to matter in many deployments. "It's not black and white," he said of the benefits of switching from third-generation to fourth-generation offerings. "[Third-generation vendors] have methodologies of channel switching that work just fine."

Fourth-generation APs, currently developed by Meru and Extricom, use a smart, centralized controller to create a large, virtual wireless cell that spans several APs, making the handoff between cells transparent to endpoint devices such as laptops and, ideally, reducing dropped connections as a user moves around a wireless LAN. As far as the device can tell, an entire office is just one large wireless zone (see sidebar for a look at the other wireless generations).

The four generations of wireless LAN networking

1st generation: Early consumer Wi-Fi equipment, minimal amounts of security

2nd generation: First release of enterprise-oriented wireless products. Access points still stand alone; security was improved.

3rd generation (3G): Most current enterprise wireless products. Central controllers help regulate AP connections, much improved security, but deployment issues remain: proper layout and channel spacing needed for maximum benefit.

4th generation (4G): All access points share a channel, with a central controller determining which access points communicate with various devices. Denser implementations become possible without risk of co-channel interference.

Extricom's APs have much less intelligence than typical offerings. They act similarly to antenna extensions that are intelligently tuned in to the appropriate device by a central switch to which each AP is directly connected. Meru's devices, on the other hand, have more intelligence in the AP, allowing them to communicate to the network on layer 3.

Each company claims its technology is superior in several ways, but King said they were similarly capable for most tasks.

These fourth generation methods also have the benefit of reducing planning complexity -- no more careful spacing of APs at set intervals, overlapping – but not by too much – connectivity zones to provide maximum range and throughput. Instead, these options can pack APs more closely to ensure stronger cover without the fear of radio interference.

But is it time to jump aboard? Maybe, maybe not. King said the technology is promising, but it is so new that network architects don't understand all its pitfalls.

"There can be some drawbacks in terms of processor power," he said. "But overall, I don't see a real huge downside doing it on the fourth-generation side versus the third-generation side."

King said he did not see a huge upside either, particularly if an enterprise could upgrade its existing infrastructure less expensively. Ultimately, he said, the market for wireless equipment was growing fast enough to support the two fourth-generation providers as well as the current third-generation providers, with plenty of customers to go around.

These fourth-generation technologies are not particularly new, but they are starting to get scrutinized from a broader market, particularly as 802.11n makes wireless a more viable replacement for traditional Ethernet office connections.

Meru was the first to deploy its technology, in 2003, and it still holds the dominant position over Extricom.

"From day one, we borrowed some of the principles of how the wireless LAN should operate from the cellular industry," said Rachna Ahlawat, vice president of strategic marketing at Meru.

At that point, Ahlawat said, most existing wireless office networks were using consumer-grade technology, which offered convenient use of Wi-Fi access based around various points of deployment: a boardroom, a cafeteria, but not necessarily the whole office.

Meru sought to change that paradigm, betting on a future where enterprises demanded more pervasive access.

"That's when we came up with this approach of putting all access points on one channel," Ahlawat said. "Our virtual cell approach allows the controller to initiate the roaming. That's why it doesn't matter if there are five people connected or a hundred, because the system manages the load."

Because AP coverage overlaps, end connections can be divvied up among nearby APs as needed without the end user's intervention or awareness. This overlapping coverage helps load balancing in ways third-generation wireless cannot.

Extricom's product debuted in late 2005 and is now in its third firmware generation.

David Confalonieri, vice president of marketing with Extricom, said the company's strategy is to approach wireless deployment problems like radio people and not like network people. In practice, that means looking at the coordination of wireless signals rather than their exact physical positioning and blanketing an area rather than precisely mapping circles of connectivity.

"The whole idea behind it comes from a different way of thinking about solving the Achilles' heel of wireless LAN," Confalonieri said.

Extricom's first customers, he said, were often those seeking to solve a specific, tough-to-crack problem: a city council that wanted to outfit its stone-walled chambers with Wi-Fi; a hospital using Citrix that demanded no loss of connection as gurneys were wheeled about.

"I don't think they saw what we were doing as radical," he said. "They saw it as a breath of fresh air, as innovation."

King said that both companies have solid offerings, with no clear winner between them.

"Neither one of them has a clear upper hand technology-wise," he said. "Extricom happens at a much lower part of the stack, while Meru has questions about processor power and ability to run over Power over Ethernet."

King also said that many enterprises might simply stick with what they know. He said there were few problems that third-generation products could not solve and that problems with Wi-Fi phones dropping calls while passing between APs – a problem that both Meru and Extricom claim to have solved – is often not that big an issue for users.

In the long run, King said, the market is big enough to support both companies, although one of them might become a ripe Cisco acquisition target down the road if its technological strengths become a must-have in the enterprise.

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