Now that wireless LAN (WLAN) costs have dropped and 802.11n technology has introduced a new level of speed, Wi-Fi is becoming a primary access technology in the enterprise. But engineers must still ensure wireless network optimization for better application performance.
While vendors work on developing wireless network optimization tools for applications, engineers are finding plenty of strategies to support video and other media-rich applications.
In this wireless technology checklist, we outline key considerations for WLAN optimization.
Plan for enough capacity (not just coverage)
The opportunity for the greatest error in a WLAN deployment actually occurs during the planning process, most often because there's a tendency to skimp on the number of access points (APs) required.
Application performance is no longer about coverage; rather, today it's about capacity. When considering traffic requirements, it's important to note that 300 Mbps and similar specs are very serious upper bounds. At my firm, Farpoint Group, we use a third of rated throughput in our capacity calculations. Always assume you will need more APs rather than the minimum required for coverage alone. It's a good idea to purchase a few spares to quickly correct capacity problems as they are discovered.
More on wireless network optimization
Optimizing network performance for WLAN real-time applications
How to ensure WLAN performance optimization
WLAN design for optimized Wi-Fi video delivery
When it comes to creating enough capacity for video, it's important to consider the number of simultaneous users, their location, video data rates (a function of resolution, frame rate, the compression algorithm used and buffering tolerance) and whether multicasting is employed.
Check for wired-side bottlenecks
Successful WLAN deployments are largely dependent upon integration with the wired infrastructure. Therefore, verifying sufficient wired capacity and appropriate network configuration is critical, as a bottleneck on the wired side will almost always be attributed initially to the wireless infrastructure.
Verify layer 1 integrity
Benchmarking and monitoring tools should be used to test for potentially harmful interference. These tools can be portable or integrated into APs. First, allow wireless networks to self-configure such parameters as radio channel and transmit power levels. Then analyze throughput, especially in the early days of a new installation.
Use inherent wireless network optimization tools
Many existing WLAN products already include class of service (CoS), quality of service (QoS) and radio resource management (RRM) settings. Some strategies will also include the use of virtual LANs (VLANs) to isolate and optimize certain traffic flows, particularly voice and video, often with separate corresponding SSIDs. Each system vendor takes a different approach here, so some experimentation may be required before optimal results are obtained. The good news is that vendors are consistently providing more automated solutions, so less work is required with newer implementations.
Keep in mind that 802.11 clients play a major role in overall performance. It's a good idea to keep both firmware and drivers up to date; vendors usually release new products without testing all of the broad ranges of operating conditions that can be present in real-world environments. With three-stream (450 Mbps) 802.11n clients now becoming available, it's beneficial to evaluate new products as they become available.
Management and assurance
Management functionality is often an afterthought in the WLAN RFP process, but it is the key vehicle for enabling operational ease-of-use and reducing operating expense. With that said, management functionality should be considered a top criterion for system selection. There are literally hundreds of functions within management and assurance, including monitoring, report generation, alerts and alarms.
Often, management systems also include traditional assurance functions, like intrusion detection and prevention systems, rogue detection and mitigation, spectral assurance and compliance reporting.
Wireless network optimization policies
Finally, it's important that everyone from the operations staff to end users understand what can and can't be done on a given WLAN and what steps management might take to deal with particular situations -- exceptional or not. It may be necessary to throttle or restrict access in some cases and limit certain types of traffic, such as types that might impact production throughput or even violate the law. Successful policy implementation requires both user education and regular review updates.
While today's enterprise-class WLANs are largely self-tuning and even self-managing, it's important to keep one's finger on the pulse of the network. Careful review of management reports and attention to user comments on perceived problems can often yield huge benefits, in terms of maintaining optimal application performance and in keeping operations costs under control.
With the WLAN taking on a key role in enterprise communications, it's more important than ever to understand the capabilities, limitations, and the tools and facilities of a chosen solution in order to assure optimal deployments and a productive user community.