Learning and Tracking the 802.11 Standard

I wrote a couple articles for the Airheads Community on learning the 802.11 standard and on how to track what’s going on with the 802.11 committee. I’ve included a snippet of each with links to the full articles in case you’d like to read more.

The 802.11 Standard and You

IEEE 802 Amendment.png

The 802.11 standard can be something of a mystery, especially when you are new to wireless networking. Have you ever wondered why wireless LANs work the way they do? WLAN configurations are full of cryptic options. Do you know what they do? Ever tried to make heads or tails of a packet capture and not understood what all the pieces are or if they are working the way they are supposed to? You can search for the answers with Google, but you might consider looking to the standard for the answers. If you really want to understand wireless, you need to gain some familiarity with the standard. Read the full article…


Learning the 802.11 Standard

imgres.jpgThe 802.11 standard can be something of a mystery, especially when you are new to wireless networking. Have you ever wondered why wireless LANs work the way they do? WLAN configurations are full of cryptic options. Do you know what they do? Ever tried to make heads or tails of a packet capture and not understood what all the pieces are or if they are working the way they are supposed to? You can search for the answers with Google, but you might consider looking to the standard for the answers. If you really want to understand wireless, you need to gain some familiarity with the standard. Read the full article…

Thanks for reading them! Feel free to give me kudos in the community if you like them, as well. :)


Unofficial #WLPC Twitter Attendee List, PHX2018 Edition

It’s a tradition here at Mostly Networks to run the unofficial Twitter attendee list for the US edition of the WLPC conference. I hope you find the list useful! It’s not updated real-time, but it will be updated at least daily as long as people keep adding themselves.

To be added, fill our the form at the bottom of the page. You can add a note to share anything of interest, like your CWNE status, podcast, that you work for a vendor, or that you really like tacos. The airport code is to help people find you if they end up in your neck of the woods. Obviously, the note and airport code are optional.

Note: This is for attendees. Sorry, if you aren’t attending I will not add you to the list.

[Last Update: 2018-03-03 00:37:42Z]

Name Twitter IATA Blog Notes
Keith Parsons @KeithRParsons SLC wlanpros.com Runs the WLPC Conferences!
Scott McDermott @scottm32768 SEA mostlynetworks.com Creator of this list and alpaca owner.
Smitty @elonsmitty BWI acceltex.com/blog/ Human Pin Cushion/Free Food Connoisseur
Rich Hummel @accelhummel SAT
Shaun Bender @welles MCI onwhereyoustop.com Tacos
Scott Lester @theitrebel MSY blog.theitrebel.com Trying to find the solution to all Lee’s problems.
W. Todd Smith @wifitodd TVA wifitodd.com CWNE#239 Does not own an alpaca!
Anders Nilsson @HerrNilsson2 ARN Hälge the Swedish WiFi Moose is riding along
craig schnarrs @the_wifi_guy DTW
Jamie Jackson @techiejames BIS First time attendee – long time listener
Brad Weldon @bradweldon PDX Tacos are always good…
Devin Akin @DevinAkin ATL divdyn.com/blog
Brennan Martin @CdnBeacon YXE 80211eh.com
Alex Burger @aaburger85 DIA wirelesslywired.com
Jake Snyder @jsnyder81 BOI transmitfailure.blogspot.com/
Drew Lentz @wirelessnerd MFE wirelessnerd.net Check out Wi-Fi stand: wifistand.com !
Veli-Pekka Ketonen @VPonwireless CLE 7signal.com/blog/ @7signal
Nick Shoemaker @nshoe18 DFW/DAL wirelessnick.com
Ryan Adzima @radzima LAS My beard has dual-5 GHz radios
Darrell DeRosia @Darrell_derosia MEM DashingDerosias.com CWJA#01 – making wifi work and taking pictures
Adrian Granados @adriangranados MCO adriangranados.com Maker of WiFi Explorer
Chris Reed @TheCMReed MHT Has pet an alpaca previously
Keith Miller @packetologist CAE www.thepacketologist.com Former meteorologist, loves to BBQ, looking to break into wireless field!
Blake Krone @Blakekrone MSP BlakeKrone.com The tie guy
Trent Hurt @wifiguy502
Jim Palmer @wirelessjimp DEN I want an alpaca that eats tacos
Robert Boardman @Robb_404 SJC robb404.com Something witty
Beef Wellington @wirednot SYR wirednot.wordpress.com I think you’ll find I’m mostly all business.
Eddie Forero @HeyEddie DEN BadFi.com ACMX #365, CWNE #160, Flounder/CEO at CommunicaONE Inc. – Mortal enemy of elevators everywhere.
Lance Romigh @ Wifi_romigh AUS wifiromigh.wordpress.com First time attendee. Looking forward to it!
Zachary Wheat @80211Zach TUL www.wlanforums.com
Patrick Nefkens @Dutch_Fi AMS dutch-fi.eu
Murray Pickard @Murray_Pickard STL No good snarky comments… :)
Mark Raats @MarkRaatsWiFi GSP/ATL raatswifi.com
Jason D. Hintersteiner @EmperorWiFi JFK www.emperorwifi.co
Dawn Douglass @Dawnpeppertech Rdu Pepper-tech.com
Jim Vajda @jimvajda CVG framebyframewifi.net CWNE #183
Martin Ericson @Vofi_Martin GOT CWNE 239, CWNT, CWNP-ALP
Brett Alger @crabby_fi BWI
Mitch Dickey @badger_fi IAD badger-fi.com #SingleChannelAdventurer and lover of all things Canadian
Curtis Larsen @curtisklarsen SLC
Amy Arnold @amyengineer DFW amyengineer.com Short on everything but snark. ;)
Aaron Scott @wifidownunder SYD blog.wifidownunder.com My wife used to have Alpacas
Myron Dingle @Mydingledangle LGA First timer!
Stephen Montgomery @StevieWireless MEM One of these days I need to get back to taking these tests.
Steve McKim @alfmckim greatwhitewifi.com/blog
François Vergès @VergesFrancois YYZ semfionetworks.com/blog
Panos Vouzis @pvouzis https://netbeez.net/blog
Tim Dennehy @justdowifi SMF Justdowifi.blogspot.com
Jason Rinaldi @jasonmrinaldi1 SAT 1/3 of the Bald Guys
Jussi Kiviniemi @JussiKiviniemi HEL www.ekahau.com/blog/ Trying to get out of Ekahau since 2002. Almost did it once!
Timo Sass @dot11_de HAM wlan.training
Nate York @dot11Nate LEX dot11nate.blogspot.com If Forrest Gump did WiFi
Mark Edwards @311_WiFi XNA I like turtles
Ferney Munoz @Ferney_Munoz SLC thewifiofthings.com CWNE #187 Tratando de construir comunidad Wi-Fi en Latinoamérica
Samuel Clements @samuel_clements BNA www.sc-wifi.com
Tim Smith @Timjsmith24 XNA
Robert Haviland @havilandweb BNA havilandweb.com My WiFe also WiFis
Jonathan Davis @subnetwork GSO subnetwork.me
Manon Mae Lessard @Mae149 YQB missmaeswifi.com Women in STEM Rock. Especially the Canuk ones!
Dan Ryan @danryan06 MHT dcrwireless.com
Matthew Norwood @matthewnorwood BNA insearchoftech.com I come for the attendee bag and the pudding filled churros. Just kidding. I love all you nerds.
Revital Gorsht @taligorsht YYZ Hockey freak
Ravi Gundu @ravi_143342 PHL Caffeinated WiFi Guy……
Robert Eubanks @@EubanksRob IAH
Troy Martin @troymart YYC Bringing the magic of Wi-Fi to the people.
Mike Atkins @MikeAtkins SBN
Terri Haviland @terrihav BNA havilandweb.com
Jonathan Finney @wifispy BNA
Tim Higgins @smallnetbuilder CHO smallnetbuilder.com There are lessons to be learned from consumer Wi-Fi too!


#WLPC_US and Free Wi-Fi Training Resources

Registration for #WLCP_US is now open! If you work in Wi-Fi you should really check it out. It’s a great place to learn and network with other WLAN Pros. New this year are Deep Dive Sessions, which are described as:

These will be two 90-minute sessions – the first to do whatever prepatory work and laying foundational information and then the next day followed up with more hands-on work for getting deep into the subject.  Each of these has a ‘kit’ of gear that is included for each attendee.

Sounds pretty slick and it should be both fun and educational. There are a number of sessions including Advanced WLAN Site Survey, to 3D printing, Python, and SDR. My friend Jerry Olla and myself will be teaching a session on Real World Mobile WLAN Testing, where we will use a single board computer and mobile devices to analyze a network using a variety of tests.

On a related note, I have a post up at the Airheads Community where I point out some of the Free Wi-Fi Training Resources that are available, which includes all the videos recorded from WLPC. If you can’t get to WLPC, want a taste of what the sessions are like, or just want to find a few free ways to learn, please check it out!


A Wi-Fi Guy Meets 3D Printing

A couple people at my office went to CES last year. One of them was showing me pictures and it seemed like everything was made with a 3D printer. Not just the usual things you expect like prototypes for various electronic toys. They showed me clothing, food items, art, jewelry, eyeglass frames and even a prosthetic arm with art incorporated into it. The sky seems to be the limited, based only on the imagination and skill of the designer.

The prices of these 3D printers are coming down, as well, with printers available under $300 and a few that are closer to $200. It wasn’t that long ago that they were $1000 or more! So what does that have to do with Wi-Fi and networks? People are designing useful objects that can be 3D printed because the market is just too small for traditional production methods or there just aren’t that many people who can use it. It’s also great for solving that problem that is unique to you, but here’s a few examples that you might actually be able to use.

Example #1: Network Jack AP Mount

Available at http://www.thingiverse.com/thing:895923

Need to mount your AP to a network jack? Problem solved, if you have a 3D printer.

Example #2: AP on a Stick Mount

Available at http://www.thingiverse.com/thing:705857

Many wireless engineers like to travel light and build their survey rig on site using painters poles and some ACME threaded 90 degree adapters. Jake Snyder (@jsnyder81 on Twitter) created this adapter to make it easy to connect various APs to this survey rig using their stock T-bar adapters. This is a good example of a product for a small niche that is really useful for those who need it!

Example #3: Aruba AP Bench Stand

Available at https://www.thingiverse.com/thing:705865

Ever need to stick an AP on a bench for testing? It ends up sitting on the cables and power supply if you aren’t using PoE to power it. This is another Jake Snyder design. He got tired of that and made this stand to hold the AP on a bench. Very niche and very nifty. The actual design is a little taller than what’s shown in this picture, so there’s a little more clearance than it looks like here. The AP pictured is sitting in his home lab.

One of the great things about these designs is that they are Creative Commons licensed, so you can improve and/or modify them for your purposes and share them with others. For example, in the network jack AP mount, I might want to reduce the height of the bar to make a cleaner looking mount. Or maybe I might want to modify the bench stand to work with another product. Unlike a mount you might buy from someone else, you can modify these fit your needs pretty easily.

3D printers are great technology to enable the creation of items we just could not have had before and aren’t just for inventors of the fancy stuff you can see at events like CES. They can be used by everyday people who just need to solve a problem. Take a look at the tech and design at sharing sites like thingiverse.com and pinshape.com. Get ideas and solve real problems or just have fun. Regardless of your purposes, 3D printing is already a great tool and is going to shape our future.

Using a 40Gb to 10Gb Breakout Cable on NX-OS

QSFP to SFP+ Breakout Cable

This cable turns a 40Gbps port into four 10Gbps ports

As part of a core refresh, I had a pair of shiny new Nexus 93108TC-EX switches. I needed to connect them to the old core switches using a QSFP to SFP+ breakout cable because the old switch didn’t have any 40Gb ports. I patched everything in and the transceivers looked fine, but when I turned up one of the 10Gb ports connected to the 40Gb ports it just started flapping. The port on the 40Gb side just says the bandwidth was 40000000 and it wasn’t breaking out the channels. I was not able to find any commands for it that were obvious in the CLI, so I start the Googling for the documentation. it took a bit longer to find than I thought it should, so thought I’d share it here to save you some time.

So, turned out I was doing it wrong. Yeah, I know we already figured that out.
The Nexus 3000/9000: Consolidated Interface Breakout configuration document has the instructions for various platforms, but it’s pretty simple:

(config)# interface breakout module 1 port 53 map ?
10g-4x Breaks out a 40G high BW front panel port into four 10G ports
25g-4x Breaks out a 100G high BW front panel port into four 25G ports
50g-2x Breaks out a 100G high BW front panel port into two 50G ports

9k(config)# interface breakout module 1 port 53 map 10g-4x
2017 Jan 20 15:10:39 9k %ETHPORT-5-IF_DOWN_INTERFACE_REMOVED: Interface Ethernet1/53 is down (Interface removed)
2017 Jan 20 15:10:39 9k %VDC_MGR-5-VDC_STATE_CHANGE: vdc 1 state changed to updating
2017 Jan 20 15:10:39 9k %VDC_MGR-5-VDC_STATE_CHANGE: vdc 1 state changed to active
2017 Jan 20 15:10:39 9k %VDC_MGR-5-VDC_MEMBERSHIP_ADD: vdc_mgr: Interface Ethernet1/53/1 has been added to this vdc
2017 Jan 20 15:10:39 9k %VDC_MGR-5-VDC_MEMBERSHIP_ADD: vdc_mgr: Interface Ethernet1/53/2 has been added to this vdc
2017 Jan 20 15:10:39 9k %VDC_MGR-5-VDC_MEMBERSHIP_ADD: vdc_mgr: Interface Ethernet1/53/3 has been added to this vdc
2017 Jan 20 15:10:39 9k %VDC_MGR-5-VDC_MEMBERSHIP_ADD: vdc_mgr: Interface Ethernet1/53/4 has been added to this vdc
2017 Jan 20 15:10:40 9k %ETHPORT-5-IF_DOWN_ADMIN_DOWN: Interface Ethernet1/53/1 is down (Administratively down)
2017 Jan 20 15:10:40 9k %ETHPORT-5-IF_DOWN_ADMIN_DOWN: Interface Ethernet1/53/2 is down (Administratively down)
2017 Jan 20 15:10:40 9k %ETHPORT-5-IF_DOWN_ADMIN_DOWN: Interface Ethernet1/53/3 is down (Administratively down)
2017 Jan 20 15:10:40 9k %ETHPORT-5-IF_DOWN_ADMIN_DOWN: Interface Ethernet1/53/4 is down (Administratively down)

So there you go. In this case, Ethernet 1/53 disappears and is replaced with Ethernet1/53/1 – 4. I hadn’t expected that parameter to be in the global config and had been expecting to find it in the interface configuration. You may now enjoy the full benefit of your breakout cables.


Paessler’s PRTG Even Monitors The Weather

While I was attending Cisco Live this year, I had the opportunity to attend Tech Field Day Extra and learn a bit about PRTG from Paessler AG. I’d heard of PRTG and even evaluated it before, but it had been a while since I looked at it. I have to say, it seems to have come a long way since I last looked!
If you aren’t familiar with PRTG, it’s a network monitoring application that runs on Windows Server 2008 R2, 2012 R2, and 2016, though they recommend 2012 R2. The system is licensed by the number of sensors with 500, 1000, 2500, 5000, and XL1 (unlimited) sizing options available. You can monitor up to 5k sensors in a VM, then they suggest switching to a physical host. Over 10k sensors, you should contact Paessler for scaling advice.
A sensor can consist of many channels, but only the sensor counts for license. You can write custom sensors that return either XML or JSON data. They have Script World, a collection of vetted links to scripts that also includes the Paessler provided scripts, just in case you didn’t know it was already included with PRTG.
They have the usual sets of thresholds and notification features that you would expect from a monitoring product. If you have the PRTG app on your mobile device you can also receive push notifications.
During their demo, one of the more interesting things they shared was adding a weather map for correlating weather events to outages. I thought that was a great idea and certainly have had times I could have used that feature. It certainly seems apropos given the major storms as of late.
They even have a new cloud solution available and you can get a free demo at my-prtg.com. That might be a great way to take a look at PRTG to see if it might fit your needs and may even provide the solution you need for production monitoring.
If this sounds interesting to you, I highly suggest you watch their presentation!


The Network Engineering Tool

The Network Engineering Tool (which I will now refer to as the netool) is the result if an Indiegogo campaign. I borrowed the unit I tested from the WLPC Lending Library. The netool is a portable, battery powered unit that when connected to an Ethernet port will provide you with information about that port, similar to a NetScout LinkSprinter (~$379), but at a much lower price point ($169). I did not really set out to make this a comparison against the LinkSprinter, but it somewhat turned out that way and I’m okay with that. It’s a natural comparison.

With the netool, you can connect it to an Ethernet port and it will provide you the following information via an app on your mobile device:

  • Connection up/down status
  • Speed of connection
  • DHCP Info
  • Public IP
  • VLAN (for tagged ports)
  • Detects LACP
  • STP Info
  • Can test QoS
  • Detect and authenticate using 802.1X
  • Switch information via CDP/LLDP
  • Verify reachability via ping for default gateway, google.com, and configurable addresses

It’s a pretty nifty tool. Here’s some screenshots of the diagnostic screen.

The netool can also provide an AP allowing direct connection to the device. It also has an interesting Host Discovery mode that can detect information from a host device (as opposed to a switch), however, I was unable to discover the macOS box I was using. This is a new feature in the latest build and I didn’t try very hard to make it work. It’s promising, though.

I was initial unable to get any useful data from the unit because it was on a very old firmware. It’s supposed to be able to update online, but the build was so old that wasn’t working. I had to power the device off and on, connect it to the network, and go to https://netool.io/updatenow/ to force a manual update. After this procedure, it worked well.

There are a few potential downsides to this device. First, it takes about 30s to start up. That’s just when you first turn it on, but you can continue to test multiple network drops without restarting it. If a network connection goes up or down, it takes several seconds to notice. This could be an annoying delay when troubleshooting. Being used to the LinkSprinter, both these delays are a minor, but real annoyance. The delay in detecting up/down changes is far more annoying than the delay in startup. Potentially the biggest downside vs the LinkSprinter, at least for the WLAN pro, is that it does not detect and report on PoE.

The ability to share results is limited to text based tools and there’s no database of results hosted in the cloud. It does have an on-board history, but that’s the only place it’s stored. Having some form of cloud based history is very convenient. Again, I have to draw a comparison here against the Link-Live service for the LinkSprinter. Link-Live allows multiple users and multiple units to be associated, allows photos and notes to be added, and can also send your results via email. It’s a much more enterprise-type solution. This is probably a bigger deal for larger shops than one-man operations, but it’s one of the things you get for the higher price point.

Lastly, the only way to get the information from the netool is through the app on your smartphone. The LinkSprinter has helpful LEDs to give you a quick thumbs up/down on a link, which can save you time. Again, how big a deal this is depends on your use case.


Despite the potential downsides I mentioned, this is still a slick device. It does do things the LinkSprinter cannot, such as provide STP info, detect LACP, and detect VLAN tags. LinkSprinter does a few things it cannot, like detect PoE. The netool has had many features added since it first was released and I presume they will continue to add new features. I think this could be a great addition for many an engineer’s toolkit, especially at it’s price point and given it’s potential for new features. If I can only carry one, I personally will continue to carry my LinkSprinter. It fits my needs better and I already own them. For a route/switch focussed engineer, I could see the netool being a better fit. Pick the tool that best fits your needs or just buy both to make sure your bases are covered. :)