There are many wireless access point vendors now with products on the market, leaving you with a tough decision -- which ones to recommend to a client and eventually use on a project. Some of these wireless access points barely satisfy the 802.11 standard, making them most suitable for homes and clients with small offices. Others have rich features that extend well beyond the standard, which are ideal for higher-end, enterprise-wide solutions.
If you're deploying a small wireless LAN for a client, then you'll likely search online for the least expensive wireless access point using a site like CNET or purchase them at your local office supply or home electronics store. For midsized or enterprise customers, you need to spend some time comparing wireless access point vendors to make the best decision based on a client's requirements. Features that seem insignificant in a smaller wireless LAN environment often have tremendous payoffs in larger ones.
Selection criteria to consider
Standards. There are two primary standards for wireless access points today: 802.11a and 802.11g. 802.11n is also available, but has not yet been officially ratified. Ratification should occur within the next year or so. The advantage of 802.11n over 802.11a and 802.11g is much higher performance. In addition, 802.11n is backward-compatible. As a result, strongly consider implementing 802.11n, but be certain to ensure that the vendor you choose will allow easy upgrades (such as firmware updates) to the future ratified version of the standard.
Interoperability. To guarantee interoperability, choose products with Wi-Fi Alliance certification. This maximizes cross-vendor interoperability: Wi-Fi-certified radio network interface controllers (NICs) will interface effectively with a Wi-Fi-compliant wireless access point, assuming that they operate in the same radio frequency spectrum (such as 2.4 GHz or 5 GHz).
Upgradeability. Because wireless LAN standards are evolving rapidly, the wireless access point you choose for a client should support firmware upgrades. It's also advantageous if the firmware upgrade can be done from a central access point, which then automatically distributes the upgrade to the other access points on the network.
Ruggedness. If the access point will reside in a client's office, plastic casing should suffice. However, warehouses and manufacturing plants will likely require the more rugged, aluminum casing. Thus, consider the operating environment and select an access point that is tough enough.
Regulatory. Wireless access point vendors must certify wireless access points with the appropriate regulatory body before offering them for sale in a particular country. This is a slow and tedious process. As a result, be sure the vendor you choose has products available for the applicable country, especially if you'll be deploying the wireless LAN outside of the U.S.
Operating temperatures. Wireless access points don't have any problems operating within typical office environments where temperatures are comfortable for humans. A warehouse or manufacturing plant, however, can have temperatures that are very hot or cold depending on the local climate. Consequently, ensure your client's new wireless access point can withstand extreme temperatures if their requirements call for these types of locations.
Security. The 802.11 standard offers wired equivalent privacy (WEP) for encrypting data sent between wireless stations, but the vulnerabilities of WEP are well documented. As a result, vendors offering enterprise-grade wireless access points generally include enhanced security features, such as IEEE 802.1X along with dynamic key allocation and management. Most wireless access point vendors also offer 802.11i and the Wi-Fi Alliance's Wi-Fi Protected Access (WPA), which are much better than the original WEP. Carefully assess needs for security, and choose a wireless access point with adequate security mechanisms.
Range. Wireless access points with range enhancements are beneficial to minimize the number and overall costs of access points. In general, longer range reduces overall costs to the client because fewer access points are needed. Be careful, though, when comparing wireless access point specifications from different vendors. One wireless access point vendor may boast long-range capability, but they may be using a higher-gain antenna. Other wireless access points, if using this higher-gain antenna, may offer the same or better range. The idea here is to read the test specifications carefully.
Installation and support tools. For enterprise wireless LANs, installation and support tools become an important aspect when choosing access points. In general, most access points have various methods, such as Telnet and HTTP, for support staff to configuration and management purposes. Enterprise-grade access point solutions offer management tools that enable easy configuration of all access points from a central, remote location.
Be aware of other enhanced features that can reduce installation and support headaches at a client site. For example, installers must choose proper radio channels when installing multiple wireless access points within close proximity to minimize inter-access point interference, which can degrade the performance of a wireless LAN. Some wireless access point vendors make your life much easier by offering automatic channel selection. The wireless access point senses the presence of other access points and attempts to adjust to a quieter channel. Keep in mind, however, that sometimes automatic channel selection causes voice calls on wireless LANs to drop connections, which can be irritating to users.
Transmit power. Most wireless access points will transmit at different power levels, such as 30 and 100 milliwatts. Some applications may require relatively lower power levels, such as when deploying access points close together to boost capacity. If you need extremely low power levels, your list of potential wireless access point vendors will be much smaller. Some wireless access points will go as low as one milliwatt, but not many do.
Antennas. Even though the antenna is a passive device, it's a vital element of a wireless LAN. Various access points have nonremovable antennas, and some have external connectors to provide flexibility in choosing antenna types. Those that support external antennas provide the most flexibility, which is especially important for enterprise solutions. Vendors generally sell different types of antennas, or you can buy through a third-party company specializing in antennas.
Price. Price obviously plays an important role when making a decision on what products to purchase for a client. An access point with a higher price, though, could be the best one to choose. As a result, carefully consider the installation and support tools that a higher-priced wireless access point may include. It could be worth the extra money if the higher-priced wireless access point saves you considerable time when installing and supporting the wireless LAN.
Availability. Even though a wireless access point vendor may have a particular product on the market, it may have difficulty fulfilling your order in time. This is especially true if you're purchasing a new model. Allow some padding in time estimates for new products, and consider availability when comparing vendors.
You can use the above criteria to produce a list of the top several wireless access point vendors and select a preferred vendor for satisfying your requirements. For larger projects, however, also consider evaluating several of the products through testing before making a final decision. For example, you could install a small prototype in a lab setting to compare and contrast security mechanisms and performance of your top three vendors. There's nothing better than a live comparison, but be sure to judge them equally using common test criteria.
About the author
Jim Geier is principal consultant of Wireless-Nets Ltd. and assists companies with the design, implementation and testing
of wireless LANs. Jim is author of over a dozen books, including Deploying Voice over Wireless LANs (Cisco Press) and Implementing 802.1X Security Solutions (Wiley).
