With 802.11n, many companies are ready to roll out larger WLANs but worried about reliability. According to Eran Karoly, Veriwave‘s VP of Marketing, the top concern expressed by IT managers and systems integrators is now: How I can make sure that all these different client devices will deliver the quality-of-service required by mission-critical applications?
“We hear that client growth and constant change is causing a lot of grief. Attempts to standardize on just a few devices are failing, and customers are asking for solutions that can test all the devices they’re seeing, under real world conditions,” said Karoly.
Worse, 802.11n signal strength is not a reliable proxy for application performance. “Customers want to capture true end user experience, not just RF power,” said Karoly. “When they find a problem, they want to know where it is and what’s causing it — for example, a new device that’s disrupting service.”
Necessity Is the Mother of (Re)invention
To address these concerns, Veriwave combined and revamped several test tools to create WaveDeploy. This new site assessment solution is designed to analyze network readiness, real-world performance, and the impact of growth and change by taking a single survey pass.
WaveDeploy generates profiled traffic to be sent and received by actual Wi-Fi client devices as they move throughout a site, recording metrics at marked intervals. Samples are smoothed to yield per-client maps showing how metrics (e.g., VoIP MOS scores, video MDI scores) compare to defined SLAs. Vendors familiar with Veriwave test gear will notice that WaveDeploy builds on the company’s WaveQoE and WaveAgent software [see this Wi-Fi Planet news release].
“You install WaveDeploy on a laptop, put that laptop on a cart with client devices running WaveAgent, and walk your facility,” explained Karoly. “Along the way, you pause and mark where you are on your floor plan to take measurements.” This technique is similar to a traditional site survey, except that several clients and applications can be measured in one pass.
Maps generated by WaveDeploy reflect each client’s experience, with roll-up views reflecting the worst experience for any client/application. Specific measurements can be viewed by hovering over any spot, but are also compared to SLAs to produce color-coded maps that make it easy to visualize where problems occurred and which devices or applications had trouble.
Later this year, Veriwave plans to add WaveDeploy WiFi, a small portable reincarnation of WaveTest hardware. WaveDeploy software can be paired with laptops, VoIP handsets, WinCE medical devices, etc. However, WaveDeploy WiFi expands this by simulating up to 64 profiled 11n devices. This enables “what if” measurements in cases where carting around dozens of devices would be impractical.
Moving From Site Survey to Site Assessment
WaveDeploy is not a traditional pre-deployment site survey tool. “With the high degree of instantaneous variability in propagation inherent in 802.11n, site surveys really are close to nonsense today,” said analyst Craig Mathias, Principal, Farpoint Group. “[WaveDeploy] is a new class of WLAN management tool designed for Layer-7 performance assurance,” he said.
Instead, Karoly refers to WaveDeploy as a life-cycle site assessment solution. Like other survey tools, WaveDeploy can take pre-deployment RF measurements. However, by generating profiled layer 7 streams and recording application-specific metrics, WaveDeploy reports results that are more readily meaningful to IT administrators and systems integrators.
Furthermore, by measuring a diverse mix of actual devices at once (not just simulated clients or a single live client), WaveDeploy can show the impact of new devices on existing clients. Result files can even be shared with vendors that use Veriwave for product testing, helping to debug problems that are not easily replicated.
Microsoft WLAN Architect Victoria Poncini has been using WaveDeploy to help her design Microsoft’s next-generation corporate WLAN. Specifically, she used WaveDeploy to characterize application coverage during a just-completed 802.11n bakeoff.
“We’ve had trouble with individual clients and their eccentricities,” said Poncini. To address this, she used WaveDeploy to measure the performance of multicast, realtime audio and video, and TCP and UDP data applications on a mix of Intel, Atheros, Broadcom, and Ralink clients.
“The ability to accurately measure individual client performance has been a huge win for the pilot,” said Poncini. “We plan use WaveDeploy for both pre- and post-install surveys to verify throughput, create SLAs, and give us a good baseline for trouble-shooting.”
The Fine Print
Despite these benefits, WaveDeploy has a few limitations. For starters, large volume client “what if” testing won’t be convenient until WaveDeploy WiFi hardware is released. First-generation WaveDeploy WiFi will only simulate SISO clients; a second-generation MIMO unit will be produced later this year.
Additionally, WaveDeploy is a measurement tool, not a predictive planner. Floor plans are just drawings; a configurable “radius of influence” determines how far each measurement is used for interpolation. If no measurement was taken close to a spot, it appears as a void on the heatmap. Furthermore, because WaveDeploy does not consider the impact of building materials, interpolated results around the corner from a sampled spot could be off.
Finally, WaveDeploy surveys can be repeated to validate fixes or verify expected SLAs. But WaveDeploy is not a continuous measurement or service assurance system; it cannot alert you to changes or automatically adjust your WLAN. But as Mathias suggested, “It’s not hard to see management or assurance tools (and sensors) incorporating this functionality over time.”
See for Yourself
Veriwave is releasing WaveDeploy Basic as a free download at www.wavedeploy.com. Basic can be installed on a Windows laptop to measure three metrics (RSSI, interference, and TCP throughput) for any local Wi-Fi adapter. This free program cannot measure other kinds of clients or applications, but it can still be useful — and give potential customers a feel for WaveDeploy.
Simultaneously, Veriwave is also releasing WaveDeploy Pro ($4,995). Pro can take all profiled application measurements using traffic sent through up to 10 client devices. This commercial version can be used to certify vendor products, efficiently validate deployed performance, assess new client/application impact, and document detected problems.
Later this summer, Veriwave plans to ship WaveDeploy Expert, capable of measuring traffic sent through up to 300 client devices (live and/or simulated by WaveDeploy WiFi). Price depends on number of WaveDeploy WiFi units. Expert will offer added benefits to larger enterprises and integrators that need to perform “what if” analysis on larger, complex, mission-critical WLANs.
