With many technologies, we've had to wait through many "years of" - as in "this is the year of VoIP" - before vendors finally delivered on their promises. That hasn't been the case with wireless LANs. The level of vendor innovation has been nothing short of astonishing, with vendors finding solutions for range, throughput, interference - you name it.

With all that, WLANs have become a magnet for all kinds of uses. But beware: As with any system, you can just pile on applications without understanding the impact.

By now, we've all become accustomed to conducting our normal business - data access, e-mail, file transfer - across our WLAN connections. And while an 802.11g (rated at 54 Mbit/s) connection will not give us the throughput we would get from the Gigabit Ethernet connection that comes standard on more and more computers (even notebooks), the freedom and flexibility we get more than makes up for any trade-off in speed. After all, few of us are moving multi-gigabyte files around all day anyway. So far, so good.

VoIP plus WLAN = congestion?
At the same time, the "year of VoIP" finally has arrived - many of us now have this as our standard voice interface. And VoIP and WLANs converge almost instantly.

Many companies offer solutions that look like traditional telephone handsets but are, in fact, native Wi-Fi devices. SpectraLink is one of the early innovators in this area. These systems can be easily integrated into the enterprise WLAN infrastructure.

And even if you haven't gotten to that point yet, you may well be using a softphone on your notebook which, when you are working wirelessly, will traverse your WLAN.

VoIP-over-WLAN (VoWLAN) providers are aware of the importance of voice - and the problems that congested links can bring. Where congestion might cause your file transfer or e-mail sync to slow down or hang briefly (which you might not even notice), that same congestion could shut down your voice conversation or degrade the quality to such a degree that you'll start telling your conversation partner - "I'll call you back on a land line."

Now VoWLAN vendors (and their enterprise WLAN switch partners) are aware of this and QoS solutions, mostly proprietary today with standards-based, will follow.

Good thing, because an "everything-over-WLAN" movement seems to be building up fairly quickly, and congestion could be more than just a "sometimes" occurrence.

Video and storage add to the burden
Video surveillance over IP appears to be growing rapidly, too. Certainly the hardware and software to implement such a solution is readily available and reasonably inexpensive. And with a post-Sept. 11 focus on security, many companies are implementing or upgrading existing security.

With surveillance, one of the biggest costs is likely to be running cable out to the various far-flung locations at your building or warehouse. Thus, using 802.11 wireless cameras is a very attractive option. But the potential of literally endless videostreaming (from potentially many cameras) could eat up a great deal of the relatively little - and shared - bandwidth that one access point offers.

If that wasn't enough, we have vendors like Iomega offering storage devices with a built-in WLAN interface. Now a back-end WLAN device can find itself being pummelled perhaps by dozens of clients hardwired to the company Fast Ethernet or Gigabit Ethernet network.

So leverage your WLAN but be acutely aware of the network characteristics of devices and applications you layer on. Avoid a WLAN pileup.

Tolly is president of The Tolly Group, a strategic consulting and independent testing company. This article originally appeared in Network World.