Sniff Wi-Fi

If I sound a little bit surly today, it's because I spent last night watching this: For those who don't follow basketball, that's the brilliant Nikola Jokic (likely named in honor of wireless pioneer Nikola Tesla !) dissecting my beloved Milwaukee Bucks . If the result of the game -- the Bucks losing by 11 points in Milwaukee -- didn't make me surly on its own, my Wi-Fi experience yesterday surely didn't help.  The Wi-Fi in the Southwest Airlines terminal at LAX was slow and unstable, and the Wi-Fi at the aforementioned game (held at the 18,717 capacity Bradley Center) was mostly unusable in the seating bowl.  But what good does it do to stay surly?  Instead, I'll offer some tips on getting Wi-Fi working at high occupancy spaces. High occupancy Wi-Fi is a sensitive issue for me for two reasons: 1) I'm sick of fixing high occupancy deployments, and 2) As a frequenter of high occupancy areas, I'm sick of bad Wi-Fi in those areas. The trouble i...

Device vendor secrecy makes Wi-Fi worse for users. "Wi-Fi is all about the users."  It's my Pinned Tweet  and my professional operating philosophy.  I don't care about AP vendor preference or network management or heatmaps or anything else that doesn't improve the user experience.  I want every device for every user to work everywhere at all times, period.  That's the goal. It is frustrating to me, therefore, that Wi-Fi device makers are so tight with their information.  I've gotten a lot of blowback for my writing and Tweeting about what a mistake it is to set the Minimum Basic Rate (MBR) above 6 Mbps .  Most of it is balderdash from BS artists and other people who don't know Wi-Fi.  A not insignificant amount, however, is from people who know Wi-Fi, at least to some degree.  And the common refrain from those people can be summarized thusly: "Wi-Fi devices use more than just RSSI to determine when to roam."  Maybe things h...

One of my favorite things to do is teach Wi-Fi, and one of my favorite tools for teaching is Savvius  OmniPeek .  The good folks at Savvius were nice enough to provide OmniPeek for the Wi-Fi classes I oversee at Global Knowledge , and so I want to offer a taste of how OmniPeek can be used to learn about Wi-Fi device behavior, specifically with the iPhone X. Savvius OmniPeek is what I call a hardcore protocol analyzer.  The "hardcore" adjective comes from the fact that OmniPeek encourages the user to view frame (aka "packet") traces.  Non-hardcore protocol analyzers focus on providing statistics and graphs.  I am a big fan of all types of protocol analyzers, but the beauty of OmniPeek is that it offers options for viewing statistics and graphs, while making its frame traces simple to navigate. One of the things I like using OmniPeek for when teaching is illustrating the different ways that Wi-Fi devices and APs use the 802.11 standard.  An example is wh...

The Wi-Fi Alliance announced its next security enhancement today, called WPA3.  The press release touts "four new capabilities", but only one of the four affects practical Wi-Fi security. As they are occasionally wont to do, the Wi-Fi Alliance  announced a new certification today via a press release featuring an artisnal blend of normal words and corporate gobbledygook.  For those who speak fluent corporate gobbledygook, here are the four enhancements of WPA3 : Robust protections even when users choose passwords that fall short of typical complexity recommendations. Simplify the process of configuring security for devices that have limited or no display interface. Strengthen user privacy in open networks through individualized data encryption. A 192-bit security suite, aligned with the Commercial National Security Algorithm (CNSA) Suite from the Committee on National Security Systems to forther protect Wi-Fi networks with higher security requirements such as gover...

Back in my day, we called it The Corner .  Nowadays, the kids call it The Trap . (WARNING: Very NSFW) The average IT professional may not view Wi-Fi "Design" as being directly analogous to the inner city drug trade.  Yet, when Wi-Fi Professionals go through the process of choosing AP installation locations, they should know what even the most novice  B.G. drug dealer knows: that The Corner is also The Trap. When embarking on a Wi-Fi "Design", some things are obvious.  Coverage is needed everywhere.  The number of available APs must be appropriate for the number of expected Wi-Fi devices.  Physical objects (walls, doors, et al.) should be accounted for. A less obvious part of Wi-Fi "Design" is avoiding Hidden Node problems.  The Hidden Node problem occurs when two or more devices on the same channel A) cannot "hear" each other, and B) can interfere with each other. The reason why Hidden Node is a problem is that Wi-Fi devices rely o...

What does Bluetooth have to do with 5 GHz Wi-Fi?  Nothing.  Bluetooth operates in the 2.4 GHz frequency band. If you look in the right spot, however, Bluetooth can teach you something about 5 GHz Wi-Fi.  Specifically, the Bluetooth 5.0 specification can teach you that Dual 5 GHz access points are a bad idea. This blog's opposition to Dual 5 GHz access points (APs) is not news to long time readers.  The ' Two Radios Are Better Than One (Unless They're Both 5 GHz) ' blog post, which details how Dual 5 GHz APs (like Cisco 3800 Series APs , for example) make enterprise Wi-Fi less stable, is nearly three years old.  Today's re-stating of the pitfalls of dual 5 GHz radio APs is due to something I uncovered while reading about Bluetooth.  I was reading the Bluetooth 5.0 specification in search of anything that might affect Wi-Fi when I happened upon this table: The middle rows of the table is most dramatic, showing that out-of-band RF activity can ...

The vast majority of Cisco Wi-Fi networks can be fixed without having to spend precious time and money on surveying, adding new access points (APs) or moving existing APs.  Here's how. Cisco has some very fine enterprise Wi-Fi products.  Unfortunately, those very fine products often get deployed in a manner that leads to connectivity and performance issues. The following steps take about ten minutes to perform, and will stabilize connectivity and performance for the vast majority of enterprise-class Cisco Wi-Fi networks.  Anything in bold  is something to click or select or check or uncheck or type. 1. Access the Cisco wireless LAN controller (WLC) interface via a web browser. 2. Navigate to WLANs  (menu) -> -> Security  (tab) -> Uncheck WPA Policy  -> Apply NOTE: Wi-Fi Protected Access (WPA) is a Wi-Fi security method that uses temporal key integrity protocol (TKIP) encryption by default.  Using TKIP encryption disables 80...