Best practices for effective Wi-Fi RF management

Wireless LANs have evolved significantly over the years, with controller-based architectures offering a system-level approach to wireless management. But with many businesses now relying on their WLANs for critical operations, it is crucial for IT managers to gain visibility into the radio frequency spectrum.

There are three major challenges enterprises face in making the WLAN mission critical: 1) a limited wireless spectrum, 2) the lack of IT expertise and resources, and 3) a rapid increase in interference sources. The unlicensed spectrum used by WLANs is shared with a variety of other wireless technologies. Its limitations are becoming more prominent as the number of devices using the wireless frequency have skyrocketed, creating an overcrowding of an already finite spectrum. IT organizations need to ensure an efficient spectrum design to optimize the available network bandwidth.

Major Wi-Fi changes ahead

Aggravating this situation is the fact that managing the RF spectrum has traditionally been beyond the grasp of the typical IT skill set. Resolving the challenges associated with RF interference requires not only the right tools but also the right training. Many enterprises lack the in-house expertise needed to troubleshoot and optimize the performance of the wireless network.A fundamental reality is that wireless devices aren't all guaranteed to play nicely together. Devices that interfere with Wi-Fi include Bluetooth, cordless phones, wireless bridges, wireless video cameras and gaming devices.

In addition, there are problematic non-communication devices that emit energy in the unlicensed band such as microwave ovens, certain lighting systems, wireless motion detectors and radar.

Over the next few years, as Wi-Fi networks transition to 802.11n technology, many will support a mix of legacy 802.11a/g as well as new 802.11n clients. Because the older clients operate at lower data rates, they can reduce the capacity of the entire network, making it even more important to preserve bandwidth by mitigating interference.

As the importance of managing the wireless spectrum increases, there are a few best practices you should keep in mind to help improve air quality without a disproportionate strain on IT dollars and resources.

* Troubleshoot. Understanding the characteristics of interference can be a complex matter. Radio waves emit different patterns depending on the source and environment. What was once relegated to guesswork has now become science with the advent of a new class of wireless chipsets that can see beyond Wi-Fi to recognize other wireless sources.

For example, a Wi-Fi system using off-the-shelf 802.11 chipsets cannot determine with any level of accuracy the source of wireless activity occurring within the same spectrum. The advent of these new "spectrum aware" chipsets now enables detection and classification -- to a very high resolution -- of any wireless activity.

* Automate. To date, the majority of tools that provide visibility into the wireless spectrum are manual and require a relatively high level of expertise to operate. IT should seek to automate wherever possible. New approaches to integrated spectrum intelligence allow the wireless system to self diagnose problems as they occur and proactively alert administrators to potential performance impacting issues.

Furthermore, these new systems can automatically adjust wireless settings to operate around interference or overcrowding --  essentially allowing the network to self-heal and self-optimize. The benefit for IT is a reduction in the man hours required to make configuration changes.

* Secure. New threats invisible to traditional wireless intrusion detection/prevention systems have emerged and can only be detected at the RF layer. These threats include proprietary wireless bridges, rogue access points configured to operate between channels, and older standards such as 802.11 frequency hopping, may each represent intrusion points into the network.

RF jamming devices that operate on nonstandard operating frequencies or use nonstandard modulation also represent a threat. IT must be prepared to respond to these threats. The good news is that with improved troubleshooting and automation, detecting and mitigating these new security threats is achievable.

* Enforce. Enforcing policies that prohibit the use of devices that interfere with the Wi-Fi network has been a challenge for network administrators. For example, 2.4GHz cordless phones can impact the performance of barcode scanners and inventory tracking applications in retail environments. Wireless networks in college dorms may become unusable due to interference from gaming devices. Whether it be a "no Bluetooth", "no cordless phone" or "no gaming device" policy, network administrators and policy makers need to work together to define and enforce appropriate spectrum usage.

Effective wireless management is crucial to maintaining a mission-critical WLAN, especially given the limitations associated with unlicensed frequencies. The lack of IT expertise and resources available for wireless management, combined with the proliferation of wireless devices consuming the spectrum, reinforce the need for a system-wide approach to spectrum management.

Emerging technologies offering enhanced spectrum intelligence promise to reduce the operational costs associated with wireless deployments. These capabilities allow IT managers to detect, locate and mitigate sources of interference across the network for faster troubleshooting and automatic RF interference avoidance.

These emerging technologies also make it easy for network administrators to assess service disruptions, receive notices about performance degradation, and take action quickly. IT should focus efforts on effective troubleshooting, automating mitigation, securing the wireless spectrum and enforcing acceptable spectrum use policies. With this approach, IT will be successful in establishing and maintaining a truly mission-critical wireless network without broader impact to IT resources and budgets.

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This story, "Best practices for effective Wi-Fi RF management" was originally published by Network World.

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