802.11g Access Points

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Wireless Access Points (APs) have become extremely popular, and the low cost of setting up a basic wireless LAN (WLAN) has fueled the technology's rapid adoption. This Buyer's Guide looks at small office/home office (SOHO) wireless APs and a few models suitable for enterprise use. Be sure to compare these products' features with your WLAN requirements; most lower-cost devices lack the management and roaming functionality that more expensive enterprise wireless solutions provide.

To create a WLAN, you need at least one wireless AP and a wireless client. The AP physically connects to your network and provides the wireless bridge that the client uses to connect to the LAN. Using APs and clients from the same vendor and product family can be advantageous and can eliminate potential compatibility headaches. However, adherence to published standards has improved interoperability between manufacturers' devices. As a result, most APs can support many different clients. But if you want to deploy many APs at a single location, you'll encounter fewer problems if you use the same vendor and product family across your APs.

The three most popular IEEE 802.11 standards provide varying speeds across different frequencies. The most widespread protocol, 802.11b (aka Wi-Fi), uses the 2.4GHz radio spectrum and supports speeds as fast as 11Mbps. The newer 802.11g standard also operates at 2.4GHz but supports a top speed of 54Mbps. The 802.11a standard supports 54Mbps throughput but operates at 5GHz, which minimizes interference with devices, such as cordless phones, that share the 2.4GHz band. Actual throughput won't approach the published top speed, but you'll definitely notice that 802.11g is faster than 802.11b.

Some AP products support multiple standards or offer upgrade kits. APs that support 802.11a and 802.11b/g contain two radios that use the 5GHz and 2.4GHz frequencies. Most 802.11g APs also support 802.11b, but check with the vendor to determine whether an 802.11b client will slow down 802.11g clients that share the WLAN. Watch out for proprietary speed-boosting technologies that work with only one vendor's hardware.

AP ranges can vary depending on signal strength and antenna type. Some APs might be configured as repeaters, which dramatically extend range and fill in dead spots in coverage. Some vendors offer boosters that increase AP range, and others offer add-on antennas that provide better coverage than do the factory antennas that are packaged with the APs.

You can configure most wireless APs over the LAN by using Secure Shell (SSH), SNMP, Telnet, or a Web page. A well-designed Web page can make configuration a snap and alleviates the need to remember console commands for proprietary features. Less-flexible APs require USB cables that must be connected to the computer that manages the AP. Some APs support Power over Ethernet (PoE) modules.

Many vendors offer entry-level devices that merge wireless APs with broadband routers. These all-in-one devices combine wireless AP functionality with a router's firewall and Internet Connection Sharing (ICS) features. Wireless-enabled broadband routers have multiple network switch ports (both LAN and WAN). If you already have a firewall, consider buying a dedicated wireless AP that has only one network port to connect to the LAN. You can use a combination device as a standalone unit simply by not using the device's WAN and Internet port. Prices for standalone AP and broadband router APs aren't significantly different.

In terms of security, look for devices that support Wi-Fi Protected Access (WPA), the successor to the notorious Wired Equivalent Privacy (WEP) standard. WPA supports 256-bit Advanced Encryption Standard (AES) encryption and automatic key rotation by using Temporal Key Integrity Protocol (TKIP) to guard the keys that encrypt wireless data. But be careful; most APs don't simultaneously support WEP and WPA, which could be a concern if you already have a large WEP deployment. Look for APs that support flexible authentication, such as 802.1x, which offloads the authentication from the AP to a Remote Authentication Dial-In User Service (RADIUS) server. In addition, most APs support media access control (MAC) layer filtering to provide extra protection from war drivers.

Coordinating communication between a wireless client and an AP requires sophisticated controls; some APs let you fine-tune these settings (although most beginners will prefer to use the default settings). Improved management usually comes with a higher price tag, however. Visit vendor Web sites to preview management features and administration programs, and check independent reviews and newsgroups to find the best product for your particular deployment.

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