Wireless networks are ubiquitous, but an enterprise environment demands much more than the simple wireless routers used on home networks. An enterprise-class wireless system needs better security, better performance, and more features than routers. Most important, however, an enterprise wireless LAN (WLAN) infrastructure needs to be able to manage the keys used to access it and support enterprise-class authentication using RADIUS and LDAP. All the products listed in this guide use a centralized controller for authentication along with lightweight proprietary APs to form a complete, self-contained enterprise-grade Wi-Fi network.

Watch Your Standards

Wireless standards have stabilized substantially in recent years. The older 802.11a, 802.11b, and 802.11g standards are well accepted. While you still need to make sure that the hardware in APS and clients support the same standards, the odds are good that if you're OK with the speeds these standards provide, you're not going to have to worry about what will and won't work on your network.

The 802.11n standard, however, raises more questions. 802.11n equipment provides much faster data transfer than the older standards, but often with a higher price. The standard—which is slated for approval by the time you read this—is widely supported by current products following the 802.11n draft standard. Draft revision 2 was the last before formal ratification. All vendors in this buyers guide support draft 2 and promise to offer free software upgrades to the ratified standard. If you plan on having your WLAN in place for years, 802.11n should probably be a priority.

802.11n is, in theory, capable of speeds over 30 times as fast as the slower standards: 100 Mbps is easily achieved in most installations, 300 Mbps is possible under the right conditions, and 600 Mbps is the theoretical maximum. Your users might be expecting the higher speeds 802.11n offers, because even consumer-level equipment is increasingly supporting 802.11n.

Note that in some cases, using different standards at the same time can hurt your network's performance. Although 802.11n supports legacy 802.11g and even 802.11b clients, if blazing-fast performance is your number one priority for your wireless network, only allow 802.11n connections.

Security

A wireless network creates security problems that wired networks don't have to face. Potential attackers can sit outside of your building, point an antenna, and potentially access everything you've got. It's well known in security circles that some attempts at wireless security are virtually pointless—both Wired Equivalent Privacy (WEP) standard and the first version of Wi-Fi Protected Access (WPA) have been completely cracked and a determined attacker can get through either protection in under a minute.

An enterprise environment should definitely support the Wi-Fi Protected Access 2 (WPA2) authentication. You might have older wireless equipment that isn't compatible with WPA2, but the risk of leaving your network exposed isn't worth taking for old equipment. Keep the older, pre-WPA2 equipment in mind, however—if you have older laptops or expect onsite guests with them, you'll need to provide an alternative, like a wired guest network isolated from your enterprise LAN for basic Web surfing.

Encryption isn't the only defense for your wireless network. A serious Wi-Fi-based vulnerability is the rogue access point (AP), where an unauthorized, usually unsecured, AP is either maliciously or innocently connected to your enterprise LAN, giving unauthorized users access at a distance to sensitive resources. Some enterprise-class wireless devices can do rogue AP detection and isolation, but the best approach is to lock down LAN access using Network Access Control (NAC).

Some enterprise-class wireless controllers also support VPN tunnels, and other features such as integration with a security suite are possible. Remember that you have to protect your network, but also remember that advanced security features often carry a performance cost, so carefully balance your network’s security and performance needs.

Performance

Modern APs can handle many simultaneous connections and lots of bandwidth, a major difference from less expensive home routers. Plan ahead and know how much bandwidth and how many connections you'll need, though, because high-bandwidth applications such streaming media, and delay-sensitive applications such as VoIP and video conferencing, are more vital as laptops and netbooks become more popular than desktops, even in enterprise settings.

An important consideration for wireless performance is range, but unfortunately your building layout and materials, not AP published range, is probably going to be the biggest factor in usable WLAN square footage. It's probably not feasible to change your building's floor plan and construction materials for the sake of a wireless network. An important concept in WLAN design is to use the minimum power necessary to cover a given area, to avoid interference with nearby areas on the same channel. Most enterprise WLAN systems can automatically set power and channel values for you; these automatic choices should be your starting point for fine tuning. Plan to use a larger number of low-power rather than a few high-power APs to achieve smooth coverage without interference.

Know Your Needs

Wireless technology has advanced quickly in the last few years, so if you need a WLAN to perform certain task, chances are the equipment you need is available. The prices for wireless equipment vary radically, however, based on features, despite the common 802.11 standards used for authentication and communication. So take a thorough inventory of what you want to connect to your wireless network now and what you'll want to connect in the future.

Remember that you'll probably be connecting much more than laptops to your wireless network. Wi-Fi enabled smart phones are the norm now, and even devices such as media players and video game consoles have wireless access. There's no telling how people will want to use your wireless network in the next few years.

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