Mobility Loop


Originally published by Mobility Loop.

Reposted with permission.

Copyright © 2006 Core Competence Inc.

All rights reserved.



Searching for Wi-Fi Hotspots




Tuesday, February 28, 2006

Written by Lisa Phifer   

Iíve been on the road recently, and that means that Iíve spent hours searching for Wi-Fi hotspots.  To be sure, there are cities where Wi-Fi seems to be everywhere.  But finding a hotspot that really meets my needs is not always that easy.Phifer

Setting expectations

For starters, Iíd like to find a hotspot thatís close to where Iím working or staying.  But when there's a choice of more than one hotspot, Iíd like to be able to compare costs: which are free, which charge by the hour, and which allow me to roam with my existing hotspot accounts?

Next, Iíd like to know which of those hotspots provide comfortable, well-lighted work areas.  I'd rather not perch awkwardly in a dim corner because that's where Wi-Fi signal happens to be strong enough to maintain a good connection.  When I have serious work to do, I'll pay an extra buck for wireless service delivered to a real table and chair. 

Where signal is spotty, Iíd rather not have to guess how to improve my lot.  "Wi-Fi spoken here" signs may advertise availability, but rarely describe intended coverage areas.  Posting Wi-Fi footprint maps would be a better way to let customers know where to sit to receive optimum (or at least passable) service.

Wi-Fi eliminates my Cat5 Ethernet cable, but still leaves me tethered to the wall Ė specifically to an unoccupied, live AC power outlet.  I can only work for so long before Iíll need some juice, and a surprising number of hotspots simply cannot deliver power to laptops, including many boarding gates and spacious hotel lobbies.  I've learned to carry a 3-way adapter to share the only available outlet with other hotspot users.

Finally, Iíd like to find a hotspot that can meet my security needs.  I simply cannot use a hotspot for business if it blocks my VPN traffic.  I refuse to supply my name or credit card number to an unsecured (non-SSL-protected) web portal.  And can I really trust that unfamiliar web server that's requesting my credit card number?  Given a choice, I prefer using WPA with 802.1X to avoid man-in-the-middle attacks, even when using a VPN to secure data sent across the Internet.

Planning and discovery

My search often starts before I leave home, using an on-line hotspot directory like JWire.  For example, I consult Starbucks to find my nearest java fix, in part because my hotspot account often works at those locations.  I check my hotelís website to see whether Iíll have free wireless in my room or lobby.  For more predictable service, I may even choose a hotel with a known hotspot provider like STSN or Wayport.

This advance planning is helpful, but thereís really no substitute for being there.  When I arrive, the cafe or bookstore may be closed, the network may be down, signal may be weak, or power outlets absent.  When my Plan A doesnít work out, Plan B is active hotspot discovery.

To discover a Wi-Fi hotspot, I can boot my laptop and use Windows XP or a NIC client to survey the air, enumerating SSIDs beaconed by nearby APs.  Moving in the direction of increasing signal strength can help locate the actual hotspot.  But this method wastes precious battery, and cannot tell me whether thereís a better hotspot next door.  And, while SSID may suggest provider identity, I cannot determine cost without attempting to connect.  Most open, unsecured SSIDs turn out NOT to be public hotspots after all.

Some providers (e.g., Boingo, Fiberlink, T-Mobile) offer connection manager programs with integrated hotspot directories.  Combining directory search results with the SSIDs within earshot can locate nearby hotspots where I'll be able to use my existing account, either directly or as a roaming user.  But this still means booting my laptop and consuming battery.  It may also mean consulting more than one connection manager -- even when provider A lets me roam with provider B, there may be security or cost reasons to use provider B's connection manager.

One provider-independent alternative for hotspot discovery is to use a shareware stumbler like NetStumbler (Windows), KisMAC (MacOS), or Wellenreiter (Linux).  Stumblers exist for nearly any OS and device.  I prefer to discover hotspots using WiFiFoFum on my Windows Mobile PDA.  If I find an appealing candidate using my PDA, I'll try to associate with it.  Eyeballing the hotspot's login page reveals cost and roaming agreements.  This avoids the hassle of booting my laptop and wasting battery where usable service isn't available.  It lets me track down the hotspot's coverage area and assess signal strength, security, and workspace conditions.  Finally, using a PDA for recon avoids risks associated with connecting my laptop to unknown SSIDs and portals.

Wi-Fi finders from companies like Kensington represent another portable platform for hotspot discovery.  These little fobs act like stand-alone, passive 802.11b/g stations, listening for SSID beacons, using LEDs to indicate signal strength.  In general, I believe that Wi-Fi finders offer too little information to be of any real help.  But I recently tried a new "hotspot detector" that did prove to be useful.

Hotspot detection

The TRENDnet TEW-429UB is a decent, if slightly large, USB 2.0 802.11b/g adapter that supports WPA2 security.  As a bonus, it can also be used by itself at a hotspot detector, displaying results on an LCD panel on the side of the USB stick.

When used in scan mode, the TEW-429UB cycles through the ISM band to display a list of discovered SSIDs, accompanied by channel number, signal strength, and security settings (open, WEP, or WPA).  In free mode, SSIDs that require WEP or WPA are omitted from the displayed list.  In discovery mode, the TEW-429UB locks onto a single SSID, periodically refreshing the signal strength meter as you attempt to narrow down the transmitter's location.

This detector is portable and easy on battery life.  It is small enough to fit in a pocket, active within seconds, and delivers enough detail to kick-start a hotspot search.  But there are limitations.  The SSIDs displayed in "free mode" are often privately-owned, unsecured residential APs.  The detector cannot spot secure public hotspots that do not broadcast their SSIDs (e.g., tmobile1x, stsn_wpa).  In congested cities, reviewing long SSID lists takes patience and good eyesight.  Finally, discovery mode sounds better than it really is -- tracking an AP down really requires a continuous signal strength display, because signal fluctuates, making transient snapshots misleading.

No silver bullet

I found the TEW-429UB useful enough to add it to my wireless travel kit.  But I still use my PDA stumbler to compare characteristics that just aren't visible to the hotspot detector, like cost and hidden SSIDs.  And I rely on laptop connection managers to suggest hotspot locations and, where appropriate, to connect to them more securely.  None of these tools eliminates investigative legwork.  But the combination makes it much easier to find Wi-Fi hotspots that really meet my needs and expectations.