So You Want to Be a Wireless ISP (WISP)?

By Adam Stone

February 01, 2002

This tutorial will give you an excellent perspective on just what it takes to roll-out WLAN services in your selected service area.

So you want to be a wireless Internet service provider. And why not? Standards such as 802.11b are making laptop wireless cards ever more affordable. As a result, airports, hotels and other public gathering places are installing wireless Internet infrastructure. As a WISP you can potentially tap into that growing market.

But where to start?
We posed the question to Butch Anton, vice president of advanced technology at hereUare Communications, a firm that provides outsourcing solutions to aspiring WISP operators. The first step, he says, is to come up with a valid business case for installing WISP architecture. Figure out who your customers will be and how much you can charge them.

Once you've done that, you need to pick your protocol. "If you are a WISP you have to choose some wireless technology to offer your customers," said Anton. Of the various 802.11 flavors on the market, 802.11b (or Wi-Fi) "is the obvious choice today, because it offers high data rates and wide acceptance" among current devices.

Now you can really get down to work

NETWORK BUILD OUT
Bandwidth and IP services selection: What are you selling. Bandwidth. What do you need? Bandwidth. Everything else will depend on finding a reliable vendor, one that offers guarantees in terms of bandwidth availability and circuit uptime. You need a circuit with good latency numbers and low packet loss. As a plus, you want a vendor with good customer service: This includes guaranteed response time for your complaints, since any down time equals lost revenue for you.

Other factors to consider include

  • If you have particular applications that require low packet loss with a target network, you want to find a vendor that peers with that network.
  • Look for redundant circuitry and IP connectivity.
  • Vendors may be reluctant to offer up a range of static IP addresses. You need at least one such address, in order to offer Network Access Translation, or NAT. Be careful with your NAT choice, though - make sure that it works with common VPN solutions.
  • Finally: How much bandwidth do you need? This will depend on how many people use the network, and the kinds of activities they will most likely engage in. Ponder this carefully, and err on the side of too much capacity.

Equipment selection: With bandwidth taken care of, it's time to consider deployment. Will you need multiple access points, based on the physical structure of your setting, along with the anticipated traffic flow? Or can you get by with a single access point? Will that access point have built-in access control and network management, or do you want a separate box to provide those functions?

If you can go with a single access point, you can focus right away on functionality issues. That means you want a server that offers an easy-to-use access control mechanism, ideally one that will handle authentication, billing and aggregate network access. (Anton's firm, for example, offers an eCoinBox solution that is licensed by manufacturers and embedded in access points to do just this.)

If you need multiple access points, on the other hand, the foremost issue is simplicity of the user experience. You don't want each to have its own access control. Instead, you need a single external management box handling access control and billing, tying together all those access points into a seamless whole.

On the high end, you can install multiple access points that are designed to work in synch with one another. A less expensive option would be to purchase individual access points (about $150 each) and tie them together on the back end with a simple home DSL router box. Once again, though, you need to consider authentication and billing functions.

Whatever equipment you select, make sure it is Wi-Fi certified, since that is the only mark of compatibility that is out there today. Want interoperability with your customers' devices? You gotta have Wi-Fi.

Also, you need to be sure your equipment provider's NAT implementation supports VPNS. Otherwise your corporate customers won't be able to reach their office email.

Site survey
Next step is to get the lay of the land. The goals of the site survey are to maximize coverage, reduce dead spots and minimize cross talk or interference between access points. It's an art unto itself. If you don't know the intricacies, you may want to contract out this bit of the job.

Equipment installation and configuration
"Installation" in this case mostly means cabling. Before you start stringing wire, figure out whether access points will be visible or hidden, and determine how you are going to move bandwidth around. After that, the bigger issue has to do with configuration.

In the case of a single access point network, configuration is fairly simple. To configure your WISP, first assign a static IP address to the access point, then enter the IP addresses for the gateway, DNS and the netmask for the network.

Will this access point be a DHCP server or a NAT server? If it is a DHCP server, turn it on and make sure the access point is configured in order to not pass DHCP packets upstream, so that you do not inadvertently pass packets up to your IP provider. You don't want the server to forward any requests past itself. Next, turn on NAT and choose an address range for your internal network, typically using a Class A or Class C address.

Make sure you disable WEP security. Otherwise you will need to distribute the WEP key to every user, and in a public-access environment that is quite impractical.

Now choose a descriptive network name or SSID, perhaps giving the name of the company offering the service. If you want to do a multiple-access-point network, you need to use the same SSID on all those access points.

Next up is channel selection: 802.11 has three channels in the U.S., (typically 1, 6, and 11) and you'll need to pick one based on your RF environment. Trial and error is the best bet here. Set your boxes to one channel set and see how they work.

Finally, create and make available instructions for configuring client machines. This should include the SSID and any network configuration parameters they will need.

For multi-access-point networks, the same rules apply - only the location of the management of the network services changes, usually to some intelligent box upstream of the access points. Follow the guidelines above and configure the upstream box accordingly.

Viola. You're a WISP.

Common pitfalls
On the technical side, the most common mistake is so obvious, it hurts. People are going to plug in their laptops to use your WISP, right? So put outlets in the walls at convenient distances. Anton said this little detail gets overlooked far more often than one might suppose.

More common still are mistakes on the business side. You may, for instance, underestimate bandwidth demand in terms of the number of users or the kinds of applications they will run. Or you may just set your prices to low. If the numbers are not adding up, it's time to reevaluate your business case. Better still, run the numbers hard before you ever start running cable.



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