Stretching wireless LANs to the limit

Everyone from network giants such as Cisco to venture-funded start-ups still in hiding are spending heavily in an effort to grab a big or bigger slice of what Gartner says will be a $2.8 billion market by 2003.

Envision a wireless LAN with:

  • Nearly limitless range.
  • Two or more times the throughput of today's wireless LANs.
  • The smarts to match bandwidth to applications.
  • Bulletproof security.

This might not be as far off as you think, if even a fraction of the wireless technologies being cooked up make their way into products and services.

Everyone from network giants such as Cisco  to venture-funded start-ups still in hiding are spending heavily in an effort to grab a big or bigger slice of what Gartner says will be a $2.8 billion market by 2003.

During the first half of the year, 135 privately held wireless companies raised $1.4 billion in venture capital, with about half of it going to infrastructure vendors, according to Growthink Research. The market research firm estimates that one in every 10 venture capital dollars spent through June went into the wireless market and that about the same was true during the corresponding period last year.

"As an investor, I focus on cost per bit," says Chris Brookfield, general partner with Northwest Venture Associates. "In wireless LANs, it is incredibly inexpensive to move data, compared with other wireless technologies like [Cellular Digital Packet Data], [General Packet Radio Service] and 3G."

Brookfield sees the wireless LAN market as a hotbed of innovation. "All of my investments [in wireless] focus on how to give users access to their applications wherever they are, whenever they want," he says. "Then, they find new ways to be productive. We've seen that over and over again in cell phones, e-mail and other things."

Here's a sampling of developments that could be coming to wireless LANs.

Greater reach

In today's wireless LANs, with power limited by the Federal Communications Commission, performance drops markedly as the distance between access points and adapter cards increases. Under the best conditions, 802.11b has a range of about 300 feet; 802.11a goes about one-third of that. At maximum distances, throughput can drop from the typical actual throughput of 5M to 7M bit/sec for 802.11b and 18M to 21M bit/sec for 802.11a to mere kilobits per second if loads of users are linked to one access point.

While vendors are trying to address the distance issue through creation of advanced silicon and better antenna designs, one of the more intriguing solutions is the use of mesh networks that provide a new way for wireless LAN radios to interact.

Wireless LANs today are based on client adapter cards that wirelessly link to an access point, which is then wired into the corporate LAN. Technically, 802.11 clients can create ad hoc connections to one another, but this isn't widely used.

MeshNetworks is one of several companies building software to create a mesh instead of a hierarchical wireless LAN (others include SkyPilotEmber and CoWave Networks). The software loads on the wireless adapter card and turns every adapter into a repeater-router, instead of an endpoint looking for an access point.

This means your wireless PDA can hop through someone else's wireless laptop, or through several, to finally reach an access point to the corporate network.

There are two results. One is the wireless LAN can extend wherever mesh clients exist. Second, because you're connecting to the nearest wireless LAN radio instead of a more distant access point, radio physics dictates that your throughput will be higher. You'll be able to run at closer to the 5M to 7M bit/sec that's typical of an 802.11b LAN.

MeshNetworks has acquired exclusive rights, including patents, to mesh technology originally created by the Defense Advanced Research Projects Agency. The company's software is essentially a routing layer, which vendors will load on their wireless LAN adapter cards and access points.

The company is developing ASICs to move this processing into silicon, instead of firmware, for faster performance, according to Rick Rotondo, director of disruptive technologies.

MeshNetworks engineers have created algorithms to minimize the power used in each hop and the latency each creates. Rotondo says each hope is less than 5msec.

The software is in beta test with a half-dozen adapter card vendors. Rotondo says the initial version of the software, called MeshLAN, will ship this fall.

Faster and smarter

Wireless LANs today, like the earliest Ethernets, are a shared medium. Technically, the wireless LAN radio spectrum of 2.4 to 2.5 GHz will remain shared. But new software, and advances in chip and antenna technology, will give users the experience of having the maximum bandwidth possible as if they were part of a switched network. Those same advances will let network executives secure, monitor and control wireless networks as never before.

"Unlike today's wired network, where you have different layers with different requirements and capabilities, in the wireless LAN world [today] you only have the access point," says an executive with one wireless start-up that's not yet come into the open. "Those access points are going down in price like you wouldn't believe. But the need for higher functionality - security, roaming, bandwidth management and so on - is going up."

The executive declined to go into detail about his start-up's technology, except to say that the goal is to create a switching architecture that can, in effect, corral the wireless packets, and precisely route, administer and control them.

The groundwork for these higher-level features can be seen in dedicated gateways such as those from Bluesocket and Vernier, both well-funded wireless start-ups. These products can make it feasible to set security levels, access controls and even traffic priorities, based on centrally maintained policies that apply to groups of wireless LAN users.

Currently, almost all these vendors promote their products as security solutions, compensating for the weaknesses in 802.11. But almost all are aiming at a larger target. "You'll see us evolving [our product] into a management node," says Eric Janszen, CEO of Bluesocket. "The security stuff will be built into future standards. To do policy decisions, for access control and network management, you have to be able to examine every single [wireless] packet that's moving between devices."

Symbol Technologies has just introduced a box, called a wireless switch that includes Layer 3 and Layer 4 switching features. This switch handles wireless packets that come to it from simplified wireless access points, which are scarcely more than stripped-down 802.11b radios.

Switching features will let wireless networks map into existing network policy and directory databases, to match specific service levels with specific users or groups.

Hybrid networks

This fall, expect to see a slew of "combo cards," wireless adapters that can connect with two or more different types of networks.

New "dual-band" chips that can shift between 2.4-GHz 802.11b networks and 5-GHz 802.11a networks will create some of this hybrid capability. The main limiting factor in 802.11b networks is that only three channels are available in that frequency range, whereas there are eight available for 802.11a.

This means you can pack more 802.11a access points closer together and support more users without interference than you can with the same number of 802.11b access points. Many corporate network executives are looking for an easy way to deploy both and manage a gradual migration to the higher throughput of 802.11a.

Dual-mode cards are a key part of achieving this migration. They will sense, select and connect (assuming you're authorized) to whichever wireless LAN will yield the best performance from a given location.

Another hybrid is an adapter that can shift the client between an 802.11b/a wireless LAN and a long-distance cellular network, such as the widespread but slow CDPD networks and the emerging, faster GSM networks.

Transat Technologies is a 2-year-old company approaching this issue from the standpoint of the wireless service providers. Its software loads onto a carrier's subscriber identification module (SIM) cards, which fit into a cell phone or PC/PDA adapter card, and identify the subscriber to the carrier's network. SIM cards use the client device's 802.11b wireless adapter to jump to the carrier's cellular net to validate and bill the subscriber.

"We make the wireless LAN look like a piece of the existing cellular net," says John Baker, Transat's president and CEO. The software is expected to be released this fall.

Advances in antenna technology will let a wireless device have one embedded antenna that can handle multiple radio frequencies.

Etenna has developed a technique that, in effect, lets a manufacturer "print" an antenna on plastic and fit it to a circuit board.

If chip builders and other manufacturers adopt this technology, it will be the basis for inexpensive, and small, radio antennas. Even more important, it will let one antenna automatically handle 2.4-GHz and 5-GHz transmissions.

Security

Currently, wireless LAN security is a mess.

The original 802.11 security scheme, called Wired Equivalent Privacy (WEP), had a number of weaknesses. Default settings for wireless LAN gear typically would simply shut off all security, including even the minimal security WEP offers.

Most initial security add-on solutions for wireless LANs attempt to adapt such established technologies as VPNs and Remote Authentication Dial-In User Service authentication. Few network executives at this stage seem ready to adopt the complex administrative overhead of digital certificates and public-key infrastructure.

The IEEE 802.11 Task Group I is finalizing work on a number of security enhancements. These will have to be implemented by equipment vendors to be effective. The work compensates for a number of WEP problems, strengthening the encryption and making WEP easier to administer.

On the drawing board.

What to expect in wireless LAN innovations.
What’s needed Technology in development
Greater reach Next-generation silicon; radical new antenna designs; autosensing adapters that link to either wireless LAN or wide-area cell nets.
More speed New 802.11a and 11b chips; antenna improvements.
More intelligence Introduction of Layer 3 and 4 switching features; intelligence distributed to access points and controllers.
Hybrid nets Autosensing and configuration between various wireless LAN frequencies, and between wireless LAN and wide-area cell nets.
Better security 802.1x authentication, with protocols for user ID/password or digital certificates; Advanced Encryption Standard.

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