By Lisa Phifer

March 12, 2010

We wouldn’t want AirCheck to be the only tool on our belt, but it could well become our first-look-go-to for routine trouble-shooting.

Fluke AirCheck Wi-Fi Tester 1.0
Manufacturer’s URL: http://www.flukenetworks.com

List Price: $1,995
Pros: Instant-on; No training needed; 1-button diagnostic tests; Field-focused time-savers
Cons: Profile config requires PC; Can’t add field notes; Solid but inflexible reporting

In large networks, efficient diagnostic tools are imperative. When mission-critical WLANs suffer interference, degradation, or downtime, users can’t work and productivity declines. But fixing Wi-Fi problems can take time, and time means money. Frontline technicians need tools that do away with Wi-Fi black magic, letting them quickly resolve most problems solo and escalate the rest along with essential data.Lee Sorenson, a computer technician at Providence Sacred Heart Medical Center in Spokane, has been using Fluke Network’s new AirCheck Wi-Fi Tester to simplify his job. Whenever one of his 1650 Wi-Fi users reports an issue, Sorensen says, “I just run up there, turn on AirCheck and in about 30 seconds I can see whether the problem is with the WLAN or not.”

Fluke’s purpose-built handheld tester was designed specifically for frontline techs like Sorenson. We found our pre-production AirCheck unit to be extremely adept at a tightly-focused set of field tasks (albeit with a few beta glitches). We wouldn’t want AirCheck to be the only tool on our belt, but it could well become our first-look-go-to for routine trouble-shooting.

Small, hardy, and colorful

The first thing we noticed about AirCheck was its light-but-rugged design. At 14 ounces, this 3.5 x 7.8 x1.9″unit fit comfortably in small and large hands for lengthy periods. According to Fluke, the tester’s field-replaceable battery lasts 5 hours per charge – long enough for a typical workday. A bit hefty for most pockets, our AirCheck survived accidental drops that might have been avoided if this unit had some type of belt clip.

When you press the “go” button, AirCheck’s screen lights instantly (below). Techs with glasses will appreciate this 2.8″ color LCD’s crisp contrast. Although font size is fixed, we found most screens easy on the eyes, aided by intuitive icons. Channel numbers are an exception – although most techs can tell those by position anyway. Anyone needing cheat sheets can find them by clicking the Legend (F2) button found on many screens.

You might be tempted (as we were) to tap AirCheck’s LCD, but this isn’t a touch screen. To navigate, thumb the arrow and select buttons below. This design makes AirCheck usable with just one hand. Columns can’t be customized or resized, but they can be sorted by clicking headings – for example, to jump right to the strongest or largest SSID.

Just the facts ma’am

Way back in 2003, we reviewed AirMagnet Handheld, acquired by Fluke last year. That PDA WLAN analyzer was ahead of its time but has started to show its age – notably absence of 802.11n. We wondered whether the N-capable AirCheck might replace AirMagnet Handheld. But after using AirCheck, we knew better. AirCheck is not a WLAN analyzer, and it’s not a “Wi-Fi stumbler.” AirCheck is a Tier 2 diagnostic toolbox, designed to make common field-force tasks extremely easy and fast.

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Like many stumblers, AirCheck displays discovered SSIDs, with drill-down to associated APs. You’ll find the usual tidbits here, including signal strength, radio type (a/b/g/n), band (2.4/5 GHz), security, and ACL status, accompanied by a few basic hints like “Possible Interference – overlaps standard channel.”

At this point, you may be thinking “Whoa, $1995 for a stumbler?” But you’d be wrong. In addition to purpose-built hardware advantages, AirCheck’s strengths lie underneath these screens. For example, selecting Channels displays a real-time utilization graph (Figure 1). Look closer and you’ll see 802.11 (blue) and non-802.11 (grey) utilization. AirCheck isn’t a spectrum analyzer but it can tell you when a Wi-Fi problem is probably caused by a non-802.11 interferer like a microwave oven or 2.4 GHz camera.

Next, tap F1 to list all APs on a given channel. Thumb down to any AP and tap F1 to Connect; AirCheck will launch a fully-automated battery of diagnostic tests at the chosen AP/channel (Figure 2). Connect tests can also be launched at Network and AP levels, causing AirCheck to scan for and select the “best” AP or channel to run those tests, much like any ordinary Wi-Fi client would.

Resulting checklists can narrow problems down to a troubled channel, AP, DHCP/DNS server or gateway. Secondary tests can be launched over successful connections, continuously pinging a designated IP to graph packet loss, RTT, and data rate. Here again, AirCheck isn’t going to replace iPerf or a LAN analyzer. Instead, it supplies just enough data to confirm low rate or excessive loss as probable culprits.

Using the Locate function, you can move closer to a target AP to re-run Connect tests, or add a found neighbor AP to AirCheck’s ACL. We had no trouble finding APs with AirCheck’s internal omni antenna, but Fluke sells an optional directional antenna for the unit’s RSMA connector.

Of course, you could develop your own test scripts to launch utilities like renew, arp, and ping on a notebook, netbook, or smartphone. Automated tests are also found in more advanced products like AirMagnet Laptop. What AirCheck brings to the table is simplicity and speed. Results are not only displayed to the user, but can be saved to AirCheck’s 8MB USB drive with a single button push to facilitate trouble ticket closure, Tier 2 handoff, or Tier 3 escalation.

Back at the ranch

Some problems can be remedied in the field, like rebooting a down AP, repositioning a weak client, restarting a hung gateway. Tougher cases require further investigation with a full-fledged WLAN, spectrum, or application-specific analyzer. Either way, AirCheck session files make offline test result review and reporting a cinch. However, those saved files must first be uploaded onto a Windows 7, Vista, or XP PC running AirCheck Manager (Figure 3).

Here again, AirCheck Manager delivers a clean, straight-forward GUI, tailored for field techs. You won’t find number crunching expert analysis here. But what you will find are large, scrollable, easy-to-use panels that display observations previously recorded during each AirCheck session, including detailed Connect Test logs.

AirCheck Manager lets you view merged results from multiple test sessions just by checking files stored on the PC or a USB-connected AirCheck. Columns can be added, deleted, moved, resized, and sorted to better focus on fields relevant to the problem at hand. We think this GUI would be even better with a search tool, discovered SSID/AP export, and the ability to append observations or case status to the AirCheck Notes field.

A PC’s larger display is useful for drilling into step-by-step test results. In the example below, we had fat-fingered an 802.1X user’s password, easily diagnosed as a failed MSCHAPv2 challenge response. A field tech could have seen this 802.1X failure on his AirCheck and handed the session file off to someone versed in EAP-speak. Although you can visually compare sessions, an automated “diff” function would be a very handy addition.

We exercise this workflow when we encountered the same connect failure in several independent guest WLANs. By comparing logs, we determined that, when AirCheck ARP’ed for its own IP address, it didn’t like Proxy ARP responses from guest WLAN gateways. We sent a sample session to Fluke engineers, who diagnose this as a beta bug (to be fixed before release). However, we also included a Wireshark packet capture when we escalated the problem.

Ready, set, go

We have mixed feelings about AirCheck’s dependency on AirCheck Manager. Entering cryptic security parameters on a handheld without a keyboard would be extremely tedious and error-prone. Instead, AirCheck Manager must be used to create and edit Profile files to be copied onto AirCheck and loaded as needed at each site.

As shown in Figure 5 (below), AirCheck supports security knobs that can accommodate diverse business needs. AirCheck can test WEP, WPA, or WPA2 Personal or Enterprise connections, applying just about every 802.1X EAP type, server verification, password-protected credentials, and AP ACL. Those per-SSID settings are grouped into Profiles; one Profile can cover all SSIDs at a given test site.

This approach makes configuring tens of AirCheck handhelds fast; corporate-standard files can be created and uploaded via USB. But it prevents Profile tweaks cannot be made on-site – unless a Windows laptop with AirCheck Manager is nearby. As a consequence, on-site customizations, such as when authorized 802.1X users are defined locally, may be impeded.One Profile edit that can be entered directly into your AirCheck handheld is ACL status. Any discovered AP can be marked as authorized, unauthorized, neighbor, guest, or flagged, with updates saved and copied back to AirCheck Manager for export/import. We agree that on-site ACL updates are handy (perhaps even necessary), but found this process awkward.

Report back to me

There will be many occasions where site audit or trouble-shooting results must be communicated beyond AirCheck Manager. Fluke facilitates this with a pair of canned reports, generated from any single session file (Figure 6).

These summary and detailed reports are nicely-formatted, information-rich, and saved in PDF or XLS format. While consistent with AirCheck’s keep-it-simple philosophy, this feature might be improved by small tweaks like generating reports from multiple session files or for selected SSIDs or APs. The XLS report is not really suitable for machine parsing, but session files are recorded in XML and might be used to generate custom reports.

Conclusion

During any pre-production hardware/beta software review, we expect a few problems. Here, our first AirCheck housed an out-of-spec oscillator that generated noise on channel 8. When we reported this symptom, Fluke moved to quickly to confirm and remedy the cause; we are told that shipping units (available late 2Q10) won’t incorporate this glitch.

In our view, Fluke is off to a solid start with AirCheck, having correctly identified and largely fulfilled a previously unsatisfied need. That said, we believe that AirCheck has room for improvement – not by adding advanced bells and whistles, but by making a few well-chosen modest refinements to satisfy common frontline needs.

AirCheck is one of those products that makes you realize what you were missing. Network engineers who trouble-shoot WLANs with laptop analyzers may think they don’t need AirCheck – and they’re probably right. But frontline field technicians who repeatedly perform the diagnostics automated by AirCheck will get more accomplished, faster, with less education. Ultimately, it comes down to ROI. If you manage a small WLAN, AirCheck may be too rich for you. If you’re responsible for supporting a large or mission-critical WLAN, AirCheck will earn its keep pretty quickly.