Jim Geier

In a previous tutorial, I provided an overview of the various frame types that 802.11 stations (network cards and access points) use to support wireless data communications. In addition to data frames that carry information from higher layers, 802.11 includes management and control frames that support data transfer. The beacon frame, which is a type […]

It’s difficult for those without radio frequency (RF) experience to determine the optimum location for access points. Without paying close attention to the factors that contribute to RF propagation, you’ll end up with spotty coverage, inadequate performance, and frustrated users. As we’ve discussed in a previous tutorial, you should perform an RF site survey to […]

Most of us are familiar with Global Positioning System (GPS) products that help us navigate while driving, hiking, boating, and flying. GPS uses a combination of orbiting satellites to determine position coordinates. This works great in most outdoor areas, but the satellite signals are not strong enough to penetrate inside most indoor environments. As a […]

On any network, especially a wireless LAN, you should plan effective operational support mechanisms to ensure that the network runs smoothly. Good operational support will improve availability, performance, security, as well as reduce costs of a wireless LAN. However, don’t depend on traditional wired-based support tools. Wireless LANs offer challenges that traditional methodologies and tools […]

The traditional architecture for wireless LANs includes access points, which forms a backbone enabling users to roam throughout a facility and interface with resources on the wired network. It’s a proven, workable method, and that’s why the use of access points is the most common method used today to fully cover a facility. You can […]

The list of schools deploying wireless LANs is increasing every day. The University of Oklahoma, Stanford, Washington’s American University and many others have already installed wireless LANs, and most other colleges are actively considering deployments. Let’s take a closer look at the benefits of wireless in colleges and consider some potential issues. Widespread, Mobile Network […]

In a previous tutorial, I discussed security threats that you must consider when deploying a wireless LAN. If you don’t implement security mechanisms beyond default settings of the access points and radio NICs, then just about anyone can compromise the information on the network. Through effective security techniques, however, you can beef up the security […]

Model Number: Enthusiast Kit ($399 MSRP) Airtouch Security Systems’ war driving kits enable just about anyone to utilize a laptop to perform security auditing on wireless LANs. All kits currently include sniffing software, 802.11b radio NIC, and antenna. Airtouch sells different versions of the kit with varying antennas types. For example, the Enthusiast Kit that […]

As with any project, you need to carefully consider all costs of a wireless LAN before moving forward with deployment. You may use your resulting numbers to compare a wireless LAN with an Ethernet alternative, perform a feasibility study for a specific mobile application, or provide the basis for a budget you’re proposing to upper […]

Most installed wireless LANs today utilize "infrastructure" mode that requires the use of one or more access points. With this configuration, the access point provides an interface to a distribution system (e.g., Ethernet), which enables wireless users to utilize corporate servers and Internet applications. As an optional feature, however, the 802.11 standard specifies "ad hoc" […]

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 […]

As an optional feature, the 802.11 standard includes the RTS/CTS (Request to Send/Clear to Send) function to control station access to the medium. Generally only the more costly, high-end wireless LANs offer RTS/CTS in radio network interface cards (NICs) and access points — you won’t find this on inexpensive home or SOHO products. Through the […]