Shulou(Shulou.com)06/02 Report--

Nowadays, wireless technology is the first choice and default technology. In most buildings, campuses, subway hotspots and wide area network settings, achieving optimal wireless performance is a key goal of the IT department.

Because radio frequency (RF) propagation always involves a high degree of variability, it is often difficult to predict the precise behavior of a given device. Variables include operating conditions, user and application traffic requirements, and features and settings of each vendor's products. Performance evaluation does become very complex when considering mobility, Wi-Fi testing, and verification.

Performance variables include throughput, coverage, time-limited traffic (mainly phone and streaming video), reliability, security, speed, etc., and most importantly, capacity, which can meet all traffic needs at any place and time.

As the price / performance ratio of Wi-Fi devices increases with the progress of standards, technology, and implementation, many IT enterprises have adopted a brute force approach: simply upgrade or add access points (AP) and Wi-Fi controllers, Ethernet switches and related hardware.

Unfortunately, this approach usually does not optimize performance and is expensive in terms of the time required by equipment and network operations professionals.

To find a better way, we interviewed some experts and came up with a set of best practices for Wi-Fi performance optimization. We focus on the three main phases of any large-scale Wi-Fi installation: planning and pre-installation; post-installation functional and performance testing and verification; and dealing with temporary performance issues (troubleshooting). We also sought advice on the necessary operational toolsets and the future direction of Wi-Fi performance optimization.

Respondents included Dr. Eldad Perahia, a distinguished technical expert in the Aruba CTO office; Matthew MacPherson, senior director of WLAN from Cisco; Jim Florwick, senior technical market engineer, and Mika Hakala, CEO of Nilesh Doshi; Ekahau, software test manager; and Bob Friday, co-founder and chief technical officer of Mike Leibovitz; Henry Ford Health Systems, senior director of product management, product manager Jerry Olla; Extreme Networks, chief mobile architect of Henry Youssef; Mist Systems. And Dr. Leigh Chinitz, Chief Technology Officer of octoScope.

Wi-Fi performance Optimization: planning Pha

Experts say that even before deciding on a particular device and its subsequent installation, much can be done to optimize solution performance and prevent operational problems.

Hakala recommends that you design for end-user quality experience (QoE), capacity, and latency, not just coverage. Understanding user location, density, and application requirements is key to ensuring capacity, Olla added. Olla also pointed out that by measuring physical space to understand RF behavior, you can avoid a large number of headaches in the future.

Chinitz recommends testing each access point under actual operating conditions and load, which can help you understand the limitations of each AP and the calculation of capacity. Add a second AP to test roaming, load balancing, and band steering, and in most cases show path loss and blind spots at specific locations.

Youssef says it is useful to conduct a "AP-on-a-stick" test in a potentially difficult environment such as a hospital. He even saw the negative impact of interior coatings on RF performance.

Mist Systems is the main advocate of indoor Bluetooth low power consumption (BLE) positioning technology and outdoor GPS technology. Friday believes that the high-density AP spacing suitable for indoor application cases also helps to optimize Wi-Fi deployment.

Florwick recommends an initial RF scan for unauthorized frequency bands, Wi-Fi or other potential interference, and select the initial Wi-Fi channel accordingly. The optimal channel bandwidth is usually a function of interference and channel utilization.

Perahia suggests that building analytical models of expected loads, even if only using spreadsheets, can be used to analyze capacity assumptions.

Leibovitz says that carefully examining the capacity, management, and local services (such as DHCP) of the rest of the network (not limited to Wi-Fi) can avoid problems because line problems tend to show up in the wireless element of the network. It is also important to consider emerging, potential, and expected traffic requirements, not just current traffic requirements, such as those of the Internet of things.

Wi-Fi performance verification

All of our participants agree that post-installation functional testing and performance verification are essential and should include at least a minimum user sample with a production application under actual operating conditions.

Youssef says he usually sees more product-related issues, especially client devices, than RF. Extensive changes in client behavior and compatibility are common, and issues such as driver settings are improperly changed by other well-intentioned end users. He recommended a rough re-survey of the space deployed each year and noted that facility organizations sometimes moved or decommissioned AP for other purposes.

Inappropriate (substandard) or defective AP wiring can lead to unexpected performance degradation, Perahia added.

Doshi recommends that you alpha test the new deployment to measure elements such as voice quality and roaming behavior before allowing users to use it. MacPherson recommends using analysis tools and taking advantage of facilities commonly used in the administrative console.

Leibovitz recommends occasional spot checks in multiple locations with specific end-user devices, even in seemingly functioning installations.

Olla points out that documentation is critical at all stages of deployment, and that even observational comments can provide reliable clues when verifying functional performance.

Wi-Fi troubleshooting and toolset

Our participants noted that the software or hardware toolset used to verify performance is also applicable for troubleshooting, so data collection has data collection and analysis capabilities covering RF, wireless network behavior, wired networks, and some data.

Leibovitz recommends that the installation collect as much operational data as possible, because patterns are easier to find when a large amount of data is available. The analysis function is very important here.

Olla recommends checking to see if there is a problem with the rest of the network's value chain, although users think the problem is defined as "wireless", Chinitz added, adding that talking to end users can produce valuable insights.

Youssef recommends that you use a third-party independent Wi-Fi analysis and assurance tool independent of the selected management console to obtain a second opinion outside the management console and to gain access to different troubleshooting policies.

Friday says real-time cloud-based management stack and API access can provide better automation and troubleshooting for end users and third-party tool vendors, allowing new use cases to be developed and deployed quickly. He also pointed out the availability of natural language query systems, which can answer questions related to experts in the network field, and expects to achieve higher speed and accuracy in the coming years.

Perahia recommends using a second AP from different vendors to test particularly tricky situations. If both results are bad, it is likely to be the customer's fault. He also recommends using package sniffing software, and even simple benchmarking tools like Iperf can be used to quickly isolate troublesome clients, AP, and traffic types.

Even after nearly three decades of widespread use of wireless Lans in local enterprises, it is clear that there is still a lot of work that can be used to enhance performance optimization and related operational elements.

The Future trend of Wi-Fi performance Optimization

The Wi-Fi experts we interviewed said they would like to see more advanced analytical tools, including advanced features based on artificial intelligence (AI) and machine learning (ML). These features have been able to automatically fix problems before the operator is aware of it. Friday sees these as autopilot networks.

Chinitz discusses virtual benchmarking, which involves testing access points (perhaps even client devices) in a specially designed RF isolation room under a series of very large conditions, and then quantifying the results into a profile that can be used to predict actual results.

According to Perahia, future operational performance analysis and optimization will depend on information collected directly from client devices, not just infrastructure. This is due to the increasing use of beamforming, multi-user MIMO and other technologies that can cause traditional sensors and guaranteed tools to be at RF zero during specific transmissions. WLAN chipset vendors may need to enhance client capabilities here to collect the required performance data.

MacPherson said that SDN may play an increasing role in data collection and optimization in the wireless portion of the organization's network. He also pointed out that the management console interface needs to be simpler, more accurate, and take advantage of the rise of AI and ML.

At the very least, there is a basic benchmark server, probably as simple as speedtest.net and as simple as iperf implemented in AP, so that you can easily analyze the actual performance of a given air link. This is a big step forward from knowing only the reported signaling rate, which can vary widely and rapidly in operation and is of little use in performance optimization anyway.

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