Sniff Wi-Fi

Apparently Wi-Fi at the White House sucks !  A journalist asked me what might help it, so I figure I'll share my response: Hi [Very Wise Journalist Who Reached Out To Me, Ben Miller, For Comment], In some ways the White House is like any other large, multi-user space and in other ways it is very different. Uncommon challenges at the White House are likely the result of security requirements and the need to maintain the historical integrity of the building.  The White House almost certainly has areas that are off-limits to AP installers and there may be limits on where cable drops can be made. There is a distinct line between good and bad solutions when AP locations are restricted.  The goal of both solutions is to increase coverage to hard-to-reach areas.  The bad solution, which is likely happening at the White House, is to increase the transmit power of APs.  Increasing AP transmit power aids downlink data sent from an AP to a Wi-Fi device, but ...

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...

The last Sniff Wi-Fi post; on why Wi-Fi professionals should stop disabling low data rates, was met some resistance.  Be it in the comments  or  on Twitter , several experienced Wi-Fi folks disagreed. All arguments in favor of disabling low rates  (the ones that were presented to me, at least) were refuted in the text of the Leave, Leave, Leave My Rates Alone blog post.  But text is a less accessible messaging method.  "A picture is worth a thousand words", as the old saying goes. If pictures will get the message across better, then pictures are what I'll use.  What follows is an illustrated look at why disabling low data rates is a bad idea. It's gauche to begin an illustrated work with text, but to understand the problem with disabling low Wi-Fi data rates one must first accept some facts about Wi-Fi devices (smartphones, laptops, etc.): 1. Wi-Fi devices -- not APs -- control associations and roaming. 2. Wi-Fi devices roam based on low rec...

Sometimes you have to return to the classics.  Who better than less-than-memorable pre-gangsta rapper Hi-C to take us there? Much like the cool kids have embraced the neon colors and late-night TV comedy of the grunge decade, so too has this blog decided to embrace its past, only with a twist.  Five short years ago I  wrote a plea asking that Wi-Fi folks stop disabling high data rates on guest networks.  And they did!  (For the most part.)  Unfortunately, the pendulum has swung too far.  Now it's time to ask Wi-Fi folks to stop disabling low data rates; or, to paraphrase Hi-C: leave my rates alone. Wi-Fi folks are always looking for ways to make wireless channels more efficient.  That is a good thing.  Wi-Fi's one limited resource is channel time, and so it is great to see more and more Wi-Fi people looking for ways to get the most amount of data across a channel in the least amount of time. Disabling low data rates is a relati...

Let's start by talking about what OnHub , Google's supercharged 802.11ac wireless router (made by TP-Link, actually) can not do. OnHub does not allow you to create multiple SSIDs.  Creating multiple SSIDs is nice because it allows a guest network to be created.  That way guests don't have to be given the Wi-Fi passphrase for the internal network.  (On the other hand, multiple SSIDs slow down Wi-Fi performance because each SSID has it's own set of Beacon frames.) OnHub does not allow you to choose your channel.  APs choosing their own channel often limits performance.  The best channel at a user's desk may be different from the best channel nearby the AP.  Usually selecting the best channel at the users' locations makes Wi-Fi work best.  (On the other hand, when the AP selects its own channel that means that the AP has the ability to change channels if a high-powered interference source is detected.) OnHub does not allow you to adjust AP transmi...

I'm giving a Webinar today at 11 am, Pacific Time on five common Wi-Fi problems and how I use AirMagnet to troubleshoot them.  NetScout (formerly Fluke Networks Enterprise), owners of the AirMagnet product line, is putting it on. You can register here:  https://www.brighttalk.com/webcast/5522/177567 Sorry for the late notice. If you miss the live Webinar, you can always access it later. *** If you like my blog, you can support it by shopping through my  Amazon  link.  You can also donate Bitcoin to  1N8m1o9phSkFXpa9VUrMVHx4LJWfratseU  or to my QR code: Twitter:  @Ben_SniffWiFi ben at sniffwifi dot com

Eleven months ago, I wrote about Fluke Networks' Ethernet testing tool, the LinkSprinter .  Now there's a new model, the LinkSprinter 300 , and Fluke was nice enough to send me one to test.   LinkSprinter 300 is basically the same as the LinkSprinter 200, except it costs an extra $100 and it has two extra features: one cool and one that I haven't tested. I really, really hate it when people say "read this" in the middle of a discussion.  It is sauce of the weakest variety.  Just frickin' summarize it.  People tend to give me the ol' "read this" either when discussing a topic that they've written about or in an attempt to cite evidence.  In both cases, a summary will do.  If you are discussing Wi-Fi sniffing with me on Twitter and you wrote a white paper saying that Wireshark is the bee's knees, then tell me why on Twitter.  If you believe that it wasn't a fact that the Earth is round until Greek philosophers proved it a few th...