Jim Geier

Model: YellowJacket ($3,200 MSRP) The Berkeley Varitronics Systems (BVS) YellowJacket is a handheld testing system designed to operate on a Compaq iPAQ so users can analyze 802.11b WLANs. A BVS designed radio unit supplied with this product slides underneath the iPAQ for truly mobile use. YellowJacket uncovers valuable information, such as access point identification, packet […]

In June 1997, the Institute of Electrical and Electronic Engineers (IEEE) finalized the initial standard for wireless LANs, IEEE 802.11. This standard specified a 2.4GHz operating frequency with data rates of 1 and 2Mbps. When deploying a wireless LAN using the initial version of 802.11, you could opt for using frequency hopping spread spectrum (FHSS) […]

As 802.11a products began shipping months ago, more and more companies have been taking advantage of 802.11a’s superior performance. 802.11a radios transmit at 5GHz and send data up to 54Mbps using OFDM (orthogonal frequency division multiplexing). The results have been very good. 802.11a products deliver excellent performance. Inside 802.11a Before discussing benefits and implications of […]

Unfortunately when deploying wireless LANs, we have to abide by the laws of physics. Wireless signals propagating through the air lose strength while encountering natural and manmade obstacles. It would be nice if RF signals would propagate without an bounds, but that simply doesn’t occur on Earth. In order to deploy an effective wireless LAN […]

The spectrum regulatory body of each country restricts signal power levels of various frequencies to accommodate needs of users and avoid RF interference. Most countries deem 802.11 wireless LANs as license free. In order to qualify for license free operation, however, the radio devices must limit power levels to relatively low values. In many cases, […]

When locating access points, system designers often use the availability of AC (alternating current) electrical outlets to base decisions on where to install access points. In some cases, companies only locate access points near AC outlets and within reach of a typical six foot electrical cord. Or, they’ll look for a convenient location to install […]

In the absence of adequate 802.11 security, quality of service, and roaming mechanisms, companies such as ReefEdge, Bluesocket, and Nomadix offer access control solutions to strengthen wireless LAN systems. The key component to these solutions is an access controller: hardware that resides on the wired portion of the network between the 802.11 access points and […]

Previously, we’ve defined RF interference and discussed general methods to minimize the problem. Potential sources of interference include cordless phones, microwave ovens, and Bluetooth-enabled devices. The presence of these types of devices can degrade the performance of an 802.11 wireless LAN. Bluetooth provides relatively low data rates for supporting short-range, wireless personal area network (PAN) […]

As part of planning a wireless LAN deployment, you need to define the tasks necessary for completing the project. This involves realizing applicable steps, such as requirements analysis, design, and installation, which are common to any system solution. To minimize deployment risks and ensure a successful project, be sure to address the following steps as […]

Voice over IP (VoIP) phone maker SpectraLink now has a license from Nortel Networks to build the UniStem IP telephony voice protocol into its line of NetLink IP Wireless Telephones. Integration of UniStem means that the NetLink phones will now work with phone systems based on Nortel voice servers such as Meridian 1, Nortel Networks […]

The 802.11 standard specifies a common medium access control (MAC) Layer, which provides a variety of functions that support the operation of 802.11-based wireless LANs. In general, the MAC Layer manages and maintains communications between 802.11 stations (radio network cards and access points) by coordinating access to a shared radio channel and utilizing protocols that […]

When planning a wireless LAN installation, be sure to carefully assess and resolve risks. Otherwise unforeseen implications, such as RF interference, poor performance, and security holes will wreak havoc. By handling risks during the early phases of the deployment, you’ll significantly increase the success of a wireless LAN. Common risks to consider With a firm […]