How to: Define Wireless LAN Deployment Risks
September 19, 2008
If you dont anticipate risks, the deployment of a wireless LAN can lead to trouble. Learn about common risks and how to avoid them.
When planning a wireless network 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, youll significantly increase the success of a wireless network.
The following are common risks to consider:
Unclear requirements. If you deploy a wireless network without first clarifying requirements, then the wireless network may not satisfy the needs of the users. In fact poor requirements are often the reason why information system projects are unsuccessful. As a result, always define clear requirements before getting too far with the deployment. For example, you may install 802.11g today to support needs for a moderate number of users accessing email and browsing the Web. Ten months later the organization may increase the density of users or need to utilize multimedia applications demanding a higher performing solution. The organization would then be facing a decision to migrate to 802.11n. Start off right after carefully considering requirements so that you choose the right technologies from the beginning.
RF interference. Devices such as 2.4 GHz and 5 GHz cordless phones, microwave ovens, and neighboring wireless networks, can cause damaging RF interference that impedes the performance of a wireless network. To minimize the risk of RF interference, perform a wireless site survey to detect the presence of interference, and define countermeasures before installing the access points. The problem with RF interference is that its not always controllable. For example, you may deploy a 2.4 GHz 802.11n wireless network in an office complex, then three months later the company next door installs a wireless network set to the same channels. This results in both wireless networks interfering with each other. A possible solution to minimize this risk is to utilize directive antennas that ensure transmit and receive power of your wireless network falls only within your facility. This would limit the impact of the interfering wireless network. You could also specify the use of 5 GHz 802.11n, which offers more flexibility in choosing channels that dont conflict with others.
Security weaknesses. The potential for an unauthorized person accessing corporate information is a significant threat for wireless networks. An eavesdropper can use a freely-available wireless network analyzer, such as WireShark, to passively receive and view contents of 802.11 data frames. Of course this could disclose credit card numbers, passwords, and other sensitive information. Avoid security risks by carefully assessing the vulnerabilities of a wireless network, and define effective security policies based on the value of information you need to protect. In some cases, you may simply need firewall protection. Other applications may require effective forms of encryption. 802.1x port-based authentication will also provide added security.
Applications interfaces. In some cases, interfaces with applications located on various hosts and servers can bring about major problems when using a wireless network. A relatively short loss of connectivity due to RF interference or poor coverage area causes some applications to produce errors. This occurs mostly with legacy applications lacking error recovery mechanisms for wireless systems. For example, a user may be using an inventory application by scanning items and entering total counts via a keypad on the scanner. If loss of connectivity occurs after scanning the bar code and before entering the count, the host-based application could log the use out without completing the inventory transaction. As a result, the application on the host may record an incorrect or invalid value for the inventory item. To avoid these types of risks, carefully define the types of applications the wireless user devices will interface with. If needed, incorporate solutions such as wireless middleware (such as NetMotion) to provide adequate handle recovery mechanisms related to wireless networks.
By identifying and solving these potential risks, youll have a much more successful wireless network deployment.
Jim Geier provides independent consulting services and training to companies developing and deploying wireless networks for enterprises and municipalities. He is the author of a dozen books on wireless topics.