Sniff Wi-Fi

The latest and greatest Wi-Fi standard is here (sort of).  802.11ac Wave 2 is now available in real-world Wi-Fi devices (maybe) and it's ready to supercharge your Wi-Fi performance (under some circumstances).   Since 802.11ac Wave 2 is brand new (based on a three year-old standard), a lot of folks are looking for clear information on it.  The technology is great (or, maybe over-hyped), but how can an organization tell whether it's time to upgrade? Luckily, Sniff Wi-Fi (in a post sponsored by Extreme Networks) has just the solution for you: an eBook!  " The 5 Essential Elements in the 802.11ac Wave 2 Business Case " covers 802.11ac Wave 2 technology, compares it to previous Wi-Fi technologies and identifies specific ways that 802.11ac Wave 2 can improve Wi-Fi performance for a number of vertical markets (no, really, it does). When it comes to Wi-Fi deployment upgrades, I find that organizations fall into one of three groups:  1) Organizations that ke

Everybody likes high Wi-Fi speeds.  Because high Wi-Fi speeds mean that the channel is being used more efficiently ( often false ).  An efficient channel means that there's more available throughput ( only in sterile test environments ) and more available throughput means that more users can be supported concurrently ( completely wrong ). Unfortuantely, high Wi-Fi speeds sometimes  ( all the time )  come at a cost.  To get higher Wi-Fi speeds, wider channels must be used ( which makes the Wi-Fi suck ).  Using wider channels means that fewer channels will be available ( plus it ups minimum RSSI requirements, which just about guarantees a bad design ).  It is therefore essential that wireless professionals analyze the environment and carefully choose whether to use 40 MHz or 80 MHz wide channels ( or they could stop wasting everyone's time and just stick to 20 MHz channels ). But this blog post isn't about choosing the correct channel bandwidth ( although it should be, b

802.11ac is the latest and greatest WiFi standard, but it's confusing.  So many questions: Is it really that much faster than 802.11n? (It can be.)  Is it worth upgrading?  (Probably not in the enterprise, but at home, absolutely.)  How fast is my device?  (Data rates as low as 6.5 Mbps and a high as 1.3 Gbps.)   Getting specific answers to 802.11ac performance questions can be a chore sometimes, but there's a simple way to check your APs.  All you need is a wireless sniffer and about five minutes. Today I wanted to find out what my 802.11ac AP is capable of.  I suppose I could've gone in search of a data sheet, but instead I decided to break out the wireless sniffer.  It was a quick and simple process. Step 1: Find the channel of your AP If you're a Mac OS X user, you can use Wireless Diagnostics .  If you use Windows, then Acrylic WiFi is probably your best option. My channel was 48. Step 2: Capture on your channel  Using a professional protocol analyz

Two years ago tomorrow Apple introduced the iPhone 5.  It was a big deal.  It was a big deal for gadget folks who wanted a bigger iPhone.  It was a big deal for wireless LAN folks who wanted users to use smartphones with speedier WiFi.   Now the iPhone 6 has been announced and it appears to be more of the same.  Gadgeteers get their bigger iPhone.  Wireless folks get their faster speeds.  Problem is, the faster wireless speeds likely won't mean anything for high capacity wireless deployments. The big news about the iPhone 6 is 802.11ac.  Yippee!  Apple has finally adopted the latest and greatest WiFi standard in a mobile device. 802.11ac has data rates as high as 6.9 Gbps in the standard, but wireless LAN folks know that's not what happens in real life.  Real 802.11ac devices top out at a 1.3 Gbps data rate when multiple input-multiple output (MIMO) antenna systems are supported, while non-MIMO devices top out at 433 Mbps. The iPhone 6 and iPhone 6 Plus are non-MIMO 8

802.11ac: A Survival Guide  is a recently published handbook about 802.11ac.  The author is Matthew Gast, a very knowledgeable WiFi guy who follows the  IEEE 802.11 Working Group closely.  I recommend the book if you work in WiFi.  It is informative.  There is great attention to detail.  All areas of the subject are covered.  But  I was left uninspired.  And my uninspiration (is that a word?) was the result of the book being short on something that I always hope to find in any technical writing: the Why. In some ways yours truly is the target audience for the book and in some ways I'm not.  I need to know the intricate details of how WiFi works.  (Point)  I already knew most of the tweaks that 802.11ac is making to 802.11n.  (Counterpoint) The physical layer is the most important part of 802.11ac, and that is where this book wins.  For example, before I read the book I was unaware that 802.11ac allows devices with different channel bonding capabilities can access a wider chann

As long time readers of this blog might know, WildPackets OmniPeek has been my favorite WiFi sniffer for nearly a decade.  Then I found out about WildPackets' OmniWiFi 3-stream 802.11n USB adapter and I fell even more in love.  Now I learn that OmniPeek 7.5 has added wireless features to the Compass screen.  A good product has been made better (though time will tell if it lasts). First, OmniWiFi: The fact that different 802.11n devices have different capabilities is one of those things that sometimes flies under the radar.  The standard may say 600 Mbps, but just on the Apple website one can buy 802.11n devices with maximum rates of 65 Mbps (iPhone 4S), 150 Mbps (iPad Mini), 300 Mbps (Macbook Air 2012) and 450 Mbps (Macbook Pro 2012). 450 Mbps WiFi devices are the ones that give WiFi pros trouble because so many sniffing tools fail to capture 450 Mbps traffic.  The popular (at least with Wireshark devotees) AirPcap NX from Riverbed, the beloved (at least by yours truly) D-Lin