Deploying Public WLANs

By Jim Geier

August 19, 2002

Public WLAN deployment is much different than private networks. Jim Geier keeps you abreast of the ins and outs of deploying a public WLAN.

The growth of public WLANs will be very high over the next few years. Companies are deploying these visitor-friendly WLANs in "hotspots" where people congregate, such as airports, convention centers, hotels, and marinas throughout the World. It won't be long until we become reliant on having WLAN access just about everywhere we go.

If you own a facility that has public areas, then consider deploying a WLAN to provide wireless broadband network services to mobile visitors. Candidate hotspots include those where people visit regularly on a temporary basis and need or desire access to network services. In some cases, the addition of a public WLAN will provide a source of revenue as you bill subscribers. Other situations might not generate revenue, but they could increase the use of your establishment.

Getting started on the right foot

If you're serious about deploying a public WLAN, develop a business plan and assess the financial aspects of the endeavor first before spending too much money. Think about whether people will actually utilize your WLAN and how much they are likely to pay. Don't depend too much on the "we shall build it, and they will come" mentality.

As a facility owner, you can deploy your own public WLAN as a "grass roots" operator. Your solution could be as simple as placing an access point within range of the visitors, and pay for an Internet connection through a local ISP (Internet service provider). This works well if the number of users is somewhat limited, such as a privately-owned coffee shop, but you'll need a more elaborate system to support masses of users and multiple locations.

A hotel chain, for example, should focus on defining requirements and properly designing the system to provide access control, roaming, and billing in addition to traditional WLAN elements. For these higher-end solutions, a facility owner generally outsources the project to a system integrator. In this case, the facility owner directly owns the network and the responsibilities in line with a wireless ISP (WISP). This could be the best way to go if you have a very clear business plan, that is, there's not much risk in achieving your revenue goals.

In some cases, companies in the business of deploying public WLANs will install the system free-of-charge and utilize a business plan similar to vending machines. The facility owner receives a small percentage of the profits by having the WLAN within their confines, and the public WLAN vendor banks on having profit left over after collecting the subscription fees from users and paying all costs. If revenue predictions for WLAN subscribers are a bit shaky, then the vending approach will reduce risks for the facility owner. Of course, you'll need to convince a vendor to install the system.

Defining requirements

Requirements define what the system is supposed to do. Spend some time near the beginning of the project to adequately identify and analyze the needs of users, existing systems, potential RF interference, and so on. Public WLANs involve defining requirements similar to private ones, but be prepared for some additional components.

Refer to my previous tutorial on defining requirements for details on common requirements types. In general, you need to define the types of applications that users will need. For example, you might enable the use of e-mail and Web browsing as a basic service. As options, you could include the use of VPNs and video conferencing.

The following are suggestions for defining requirements that pertain specifically to public WLANs:

  • Keep the user interface as open as possible. With public WLANs, be sure the solution interfaces with the widest possible number of users. This maximizes the number of subscribers. Most WLAN users today have 802.11b radio NICs, but plan ahead and insist on access points that support both 802.11b/g and 802.11a.
  • Provide adequate authentication mechanisms. To regulate access to the network, the system needs to include a process that requires users to subscribe and log in. RADIUS is the most common authentication database in use today, but be sure to require authentication elements that provide a level of security consistent with application requirements.
  • Enable widespread roaming. If you plan to deploy a public WLAN at multiple sites, then you need to accommodate users that will be roaming from site-to-site. Consider interfacing with other WISPs to provide the widest possible roaming capability for your subscribers. In that case, however, you'll need to include a settlement function that mediates the financial transactions. For example, you'll want some of the profits applied to your account if one of your subscribers operates within an area covered by a different WISP. Your WISP partner will want the same in return.
  • Consider implementing local advertisements. A public WLAN can provide a mechanism to deliver advertisements to subscribers similar to other online services. In fact, you can provide a free subscription to users for basic Internet access, and drive ads to them with hopes that they'll purchase enough from the ads to offset the cost of system. Keep the advertising to a minimum, though, especially when users are paying for services.
  • Virtual Private Networks (VPNs). In hotspots where business travelers may be present, ensure your public WLAN supports VPN traffic. In many cases, people on the road must use their company's VPN to access corporate resources.
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