Although we find Ethernet cable to still be the dominant means for connecting customers to the Internet gateway (or among each other), the demand for doing this via 802.11 Wi-Fi access, or providing Wi-Fi access in addition, is growing rapidly. Additionally, a growing number of the customers want to use Wi-Fi among their own equipment (often, they're showing Wi-Fi products, or Wi-Fi-enabled ones... or it's easier -- for them -- to use wireless than cables).

Wi-Fi seems like a natural fit for ad-hoc networks, and it is...but we've had some interesting experiences with it, and learned some lessons along the way. Fortunately tools for creation and management of wireless event networks are starting to become available, and we'll be taking a look at some of the ones I've found most useful.

Here's some "lessons learned" advice, in case you find yourself asked to provision WLAN service, particularly on turf that your company doesn't own and control., to help you achieve a successful event.

Steps To Successful Wi-Fi

Typically we set up several Access Points (APs), check the signal strength around the venue, and declare victory... only to find that when the event starts, a gaggle of APs nobody told us about are suddenly present, half the users want to use streaming media, and the other half can't get the cards their IT departments gave them at the last minute to work in their laptops. (We love Wi-Fi, but operating it can be a three-ring circus, and it's not easy being the ringmaster with all those clowns running around.)

The Wi-Fi-related problems we've run into fall into several groups: rogue APs, bandwidth hogs, poachers, and competing events. Some of these problems can are straightforward, but some are more problematic. Here are some tips for keeping your clients happy, and some suggestions for adding value you're at it.

1) Do A Site Survey, Of Course

Check out the physical site and RF environment before the event. Not just for other Wi-Fi setups, but for all the other radio activity in the area. 802.11b and g both operate at 2.4 GHz -- the frequency shared by cordless phones, microwave ovens and even Bluetooth devices.

Dedicated RF spectrum analyzers are expensive, but I've been told there are free applications you can download from your 802.11 card manufacturer that will turn your PDA into a cheap RF spectrum analyzer.

Personally, I believe that a visual inspection will probably give you a pretty good idea of what's likely to be a factor. In fact, unless you're going to monitor the RF environment for a few days, talking to people in the building will probably tell you more than taking a snapshot with an expensive spectrum analyzer. (If you want to look into serious spectrum and protocol analyzers, you might like to read Andy Dorman's article: "Wireless LAN Analyzers: The Ultimate Hacking Tool?.)

At the bottom end of the price spectrum are devices like Kensington's WiFi Finder ($29.95), which fit on a key ring and have LEDs to show the presence of Wi-Fi devices. They're better than nothing, and they're cheap, but they only tell you if someone has an access point around, and you need to know much more.

You can find out what you need to know by taking along a copy of NetStumbler (www.NetStumbler.com), which is free (they would appreciate a donation, but it's voluntary). This indispensable application turns your laptop or (using MiniStumbler) PDA into a portable tool that shows networks, active 802.11 devices, channel usage, MAC and IP addresses, and lets you query them to see whose they are. Of course, many of the addresses you'll see are internal and won't tell you anything, but the wealth of information about the Wi-Fi environment you'll get make this a must have.

Physically, you'll want to check out the location for line of sight obstructions for Wi-Fi signal access. A good rule of thumb for of 802.11b coverage in an unimpeded space is a 250 foot radius per AP. Sheetrock walls won't stop a signal, so be sure to ask the venue owners if there are any other events going on at the same time, and who is handling their networking. If at all possible, get contact information for the other events so that you can work things out later when conflicts arise.

2) User Survey

Find out who the users are and what they'll need. You may know in general, but asking helps both of you understand their needs and options. I think online forms are the handiest way to collect this information because they're quick, reasonably painless to fill out, and drive potential clients to your site.

Make sure you get the following information: Firm Name, Attendee Contact Information (Name, Cell Phone and Email address), Company Technical Support Phone and Email Address, Estimated number and type of machines to connect, and general web based applications expected to be used.

You can go ask about specific hardware too, but the more you ask for, the less likely you'll get it. Remember that you can always download drivers when you need them in order to get balky machines connected, and remember to carry a mini USB storage device with you for quick file transfers from your computer to clients.

Be sure to bring several Wi-Fi and external Ethernet adapters that you know you have the drivers for. We recommend a mix of PC Card and USB types to cover the bases, and suggest you lean towards higher quality brands. When all else fails, renting clients a laptop can save the day, so keep one on standby. Often vendors just need to be able to demonstrate something on the web, and don't actually need their own system.

3) Having Wi-Fi doesn't mean not having wired Ethernet.

It's important to remember that Wi-Fi is only a piece of the access puzzle, not the whole pie. While it's appropriate for web browsing and email checking, you can only sustain about 11 mbps (802.11b) for most of your users, which is only about a tenth of the throughput of a 100BaseT Ethernet connection. 802.11a and g, are faster, but still sluggish by comparison. Wireless solutions work best in low conflict areas like homes, cafes, and boardrooms. Anytime you have more than 30 people in a room trying to hook up you've got too much traffic and not enough channels. The solution for high traffic applications is to use Wi-Fi to augment your wired network connections.

4) Turn on the WEP

We've seen a lot of events not bother to even turn WEP on for their Wi-Fi APs, and while we understand the inconvenience of having to set up even simple security, we believe it more than pays itself back in terms of overall quality of service. True, WEP can be circumvented, but we're primarily concerned with QOS rather than security and it makes you a harder target, which people tend to avoid. Some people have tried getting their users to provide MAC addresses before the event, which would be a great solution... but most users don't even know what a MAC address is, and will probably show up with a different machine than they planned anyway.