Clear To Send: Wireless Network Engineering

This week, we have Troy Martin on the show to talk about IoT. We talk about the IoT landscape and which wireless technologies are used both at home and in the enterprise space. Troy Martin, CWNE #90 and CWNE Advisory Board Member, works as a Principal Consultant for Trogen Consulting. He also co-host a podcast called “Channel 42” where he talks about Wi-Fi and IoT and blogs at WiFiVitea. We are also giving away a voucher for the CWNP CWISA exam. Check out the form at the bottom of this page to participate. We would like to thank CWNP for providing this voucher to us! Enjoy the episode: This image details the different channels and channel widths used over the 2.4GHz frequency band by the most popular IoT wireless technologies: source: https://www.silabs.com/products/wireless/learning-center/wi-fi-coexistence The following image displays different IoT wireless technologies you could use based on their operating range: This is extracted from a report from Keysight Technologies: The-Internet-of-Things-Enabling-Technologies-and-Solutions-for-Design-and-TestDownload

Following episode CTS 252 where we talk about our general Wi-Fi Design methodologies, we wanted to do a deep dive on warehouse Wi-Fi. Enjoy the episode: We covered a few things that are even more relevant in a warehouse / manufacturing environment: * Installation heights* Choosing the right antenna* Choosing the proper installation type* Choosing the right antenna orientation* How to take into account the attenuation of racks or machinery* How to study signal strengths at different levels* How to take roaming into account* Channel planning* And more… Additional Links & Resources * CTS: 252 https://www.cleartosend.net/our-wifi-design-walkthrough/* Warehouse Wi-Fi WLPC 2018 (François Vergès and Glenn Cate): https://www.youtube.com/watch?v=GHLNVywpARE&t=189s* Difficult Wi-Fi in warehouses and Manufacturing Facilities Webinar: https://www.youtube.com/watch?v=tBZwt0KS50o&t=7s* How to design Wi-Fi for a 720k sq. foot Warehouse (Wi-Fi Ninjas): https://www.youtube.com/watch?v=h8MpOhtNmRs* Wi-Fi in Manufacturing and Warehousing Webinar: https://www.youtube.com/watch?v=I1YBIMFWUU0

We’ve had many discussions about using APIs with Wi-Fi. Mostly it’s been around learning Python, practicing with simple projects, or using scripts to enhance our work with clients. Today, we bring on Jonas Dekkers from Wiflex. Wiflex is an cloud-based service to help organizations onboard their customers and end users onto the Wi-Fi network. Jonas helps solve challenges from the hospitality space to education. With Wiflex, people can use a self-serve station to get onto the Wi-Fi network securely. For example, walking into a hotel space it would not be secure if everyone used the same pre-shared key. With Wiflex, everyone can get their own unique key. What’s interesting about Wiflex is it is API-first. What does that mean? Their solution works with Wi-Fi systems that have an API. That means they work with Ruckus, Mist, Extreme Networks, and Meraki. Because of the API available from these vendors, Jonas has built a cloud-based service leveraging API. That’s an awesome achievement! Listen to the episode and let us know what you think below in the comments.

In this episode, we are welcoming John Breth to talk about the Mist AI JNCIA certification. John Breth work as an IT/Cyber Architect. His focus is security but he decided to go for all Juniper JNCIA certifications last year, which led him to try out the JNCIA Mist AI certification. It was nice to hear from him as he is not focused on Wi-Fi on the regular basis. Apart from that, John has built a name for himself producing really nice network focused videos on his Youtube channel: CyberInsight Feel free to check his content out if you want to learn more about networking and Juniper. Here is where you will be able to find him online: * Twitter: https://twitter.com/JBizzle703* Youtube: https://www.youtube.com/channel/UCmJJUewPWfnyzvZRrFHlykA* Blog: https://jbcsec.com/insights/* Company website: https://jbcsec.com/links/ Resources * JNCIA-MistAI Page: https://www.juniper.net/us/en/training/certification/certification-tracks/mistai?tab=jncia-mistai* Mist Master training: https://courses.mist.com/* Getting started with Wi-Fi (e-learning): https://learningportal.juniper.net/juniper/user_activity_info.aspx?id=11573* Practise exam on Junos Genius: https://www.juniper.net/us/en/training/junos-genius/* Mist AI Official Training: https://learningportal.juniper.net/juniper/user_activity_info.aspx?id=11460

We’re providing a view of how we use Ekahau Pro to perform predictive modeling of an office floor plan. In a future episode, we will do a walkthrough of a warehouse predictive model. François and I perform Wi-Fi design differently. This episode we talk about our differences, the goals we’re trying to achieve, and an explanation of why and how we do what we do. The purpose of this episode is to show you an example. We hope that it provides guidance for you if you have any questions about Wi-Fi design. We’re open to any questions, comments, and feedback. We encourage sharing your perspective and tips for others to learn from. The Wi-Fi design example uses a real office plan provided by a client. We use coverage and capacity requirements that will develop the rest of our Wi-Fi design. Some of the things we cover in our Wi-Fi design: * Access point selection* Modifying access points* Considerations of wall materials* Scale* Channel and Transmit Power planning* Requirements* And more

In this episode, we’re going to cover a small topic of the CWAP certification. We’re taking a look at the frame exchanges that occur during 802.11r or Fast BSS Transition. In our scenario we’ll use my iPhone which associates to AP1 and roams to AP2. Without 802.11r, the roam will take additional time to complete. 802.11r enables that roam to complete in less time. There are two methods Fast Transition will use when a device is moving from its current AP to another AP: * Over-the-Air (OTA)* Over-the-DS (OTDS) (distribution system) In OTA, a device roaming to another AP will communicate with that target AP directly during the roaming process. In OTDS, the device roaming to another AP will initiate the process with Action frames sent through its current AP destined to the target AP. Then the roaming process is finalized with direct communication with the target AP. Over-the-Air Let’s take a look at the messages being used by a device to its target AP. There are four frame exchanges to look at: * Message 1 – Authentication Request from the device (originator) to the target AP* Message 2 – Authentication Response from the target AP destined to the originator* Message 3 – Reassociation Request frame from the device to the target AP* Message 4 – Reassociation Response frame from the target AP to the originator Let’s take a look at the full frame exchange process Within the Beacon, Probe Response, Authentication, and Reassociation frames you will find the Mobility Domain information element. Access points part of the same ESS will contain the same Mobility Domain Identifier. There will also be a Fast BSS Transition over DS element which will indicate whether this frame is OTA or OTDS. Over-the-DS Let’s take a look at the messages being used by a device to its target AP. There are four frame exchanges to take note of: * Message 1 – Fast Transition Request Action frame originating from the device (originator) to the current AP with the target AP’s BSSID in the Address field of the frame* Message 2 – Target AP sends a Fast Transition Response frame to the originator* Message 3 – Originator sends a Reassociation frame destined to target AP* Message 4 – Reassociation Response frame from the target AP to the originator Let’s take a look at the full frame exchange process Wireshark filter to find Over-the-Air or Over-the-DS Fast BSS Transition frames and which mode they are in: wlan.mobility_domain.ft_capab.ft_over_ds Links and Resources * Episode 198* PCAP Files* Listener Survey

After 47 episodes we’re closing the book in another year of podcasting. We missed 5 episodes which is not bad for publishing every week. We run this podcast in addition to our careers and while being with our families. We’ve certainly enjoyed the process along the way and have learned a lot. There was plenty to learn since we’re still in the pandemic. This year we were able to top 525k all-time downloads of the podcast. We’re happy with the results since we focus on Clear To Send part-time, only utilizing social media to share our episodes. And with the reshares from our listeners, we’re super grateful for your support! The show is now surpassing 15k downloads per month. A big shift for the podcast since July 2020. Around this time we thought downloads would decrease due to people staying home and doing less traveling. But as we approach 2021, we want to ask for your help by filling out our yearly listener survey. It allows us to learn how we’re doing and to learn more about our listeners. We want to give shoutouts to those who have been our top supporters and who have been active in our Slack workspace: * Gjermund* Carlos* Lariana* Keith* Matt Here are some statistics for the podcast. Top 10 Episodes of 2020 * CTS 205: 5 Tips for Migrating to the Cisco Catalyst 9800* CTS 206: A Look Into 802.11k* CTS 223: How Does an Antenna Work?* CTS 211: A look into 802.11v* CTS 209: Python and Wi-Fi* CTS 204: CWNP Certifications* CTS 207: The New CWNP Track with Tom Carpenter* CTS 202: Building a Lab* CTS 218: 6GHz PSD & AFC with Chuck Lukaszewski* CTS 213: How to Approach a Wi-Fi Validation Survey Top 10 Countries Listening * United States* United Kingdom* Canada* Australia* India* Germany* Sweden* Netherlands* France* Japan We did set engagement goals at the beginning of the year. Here’s how we did. * Twitter: get to 3500 followers. Previously it was 2606. Currently at 3190.* LinkedIn: get to 1000 followers. Previously it was 588. Currently at 1049.* Slack: grow the community to 400. Previously it was 242. Currently at 441.* Email list: grow it to 1000. Previously it was 724. Currently at 896. We released our first course, A Practical Guide to Wi-Fi Site Surveys and learned a lot from the whole process. There’s a lot of work into designing and making an online course. Aside from making course material, we also needed to learn how to distribute and sell the course.

We have the author of the best Wi-Fi apps for MacOS, Adrian Granados, joining us on this  episode. Adrian went full-time with his company, Intuitibits, to dedicate more time to his applications so we can be better working with Wi-Fi. We last had Adrian on the show on Episode 7! He describes what it was like making the transition to Intuitibits in June 2020. We can relate to the business aspect of things when trying to focus on your main purpose. It’s an interesting story and we fully support Adrian. WiFi Explorer Pro 3 has plenty of features to be happy about. Adrian describes the amount of custom columns that can be added to the main pane and with better management through profiles. Sometimes you can have too many columns and you lose sight of the BSSID but now you can pin that column so it sticks when scrolling, or pin any column you desire. These are just some of the newest features added. His newly updated application, Airtool, is a finalist for 2021 Product of the Year, so go please vote. Airtool turns your Macbook into a capture utility by using your built-in Wi-Fi adapter. Capturing frames is now easy without all the complicated commands. Download WiFi Explorer Pro (affiliate link)Download Airtool 2 (affiliate link)

This episode comes from our live stream of Wi-Fi Coffee Hour where we discuss industry news. Watch the video version below. And be sure to follow us on YouTube! I’ve had a brand new access point sitting in a box for a while now, why don’t we unbox it. And what are the differences between the Meraki Wi-Fi access points? Should we be trusting magic quadrants? We give our thoughts on Juniper’s big move to becoming a leader. What’s up with UNII4? The more spectrum the better! And a whole lot more for Coffee Hour. Grab a fresh cup and join us. 0:00 – Starting Soon 3:22 – Start of the stream 6:01 – New CWNEs 10:31 – Magic Quadrant 20:45 – Unboxing Meraki MR36 27:33 – UNII4 24:19 – WBA Wi-Fi 6 Deployment report 48:56 – 6 GHz in Canada, what’s the latest? 51:47 – Good Wi-Fi analysis from Gjermund – https://gjermundraaen.com/ 53:40 – Conclusion – what are you thankful for?

Celona joins the podcast to show us the platform capabilities of Celona Edge and enterprise integration. We also take a look of a live demo running on San Jose State University. Take a look at how CBRS can be used in a private network environment. For a visual look at the solution, check out the YouTube video. Andrew von Nagy starts off with a solution overview of Celona Edge, the cloud-native private mobile controller. This is the enterprise packet core to provide the 3GPP standards-based capabilities and interfaces. There is the Celona Orchestrator which is the AI-powered operations console. The Orchestrator has API integration to other enterprise systems to create solutions across the network. It provides management for the private LTE/5G network. Then to provide connectivity to devices there are the Celona SIM/eSIM cards for authentication and the Celona RAN, the enterprise LTE/5G access points. What we have here is a fully operated and owned enterprise LTE/5G network with full visibility into the applications, traffic flows, and data the clients are using. Celona recorded this demo over their own deployment in San Jose State University, showing us how they were able to connect over the private network and show the types of speeds that were cable. What use cases can you see with Celona in your network?

Which tools are best to use for Wi-Fi troubleshooting? Maybe you’re using a handful of tools to complete the job. Each tool performs a specific function and in the end we need to merge the data collected into a single report or next action. For a few months, I’ve been testing the netAlly EtherScope nXG. It’s handheld tool with multiple functions. It performs tests on wired and Wi-Fi networks. So in this episode, François and I speak about how the EtherScope nXG and also the AirCheck G2 can help Wi-Fi engineers in their day to day jobs. But the handheld tools are much more powerful than that. We could have others perform these tests, others who may not be networking experts. The functions are intuitive, especially when it comes to netAlly’s AutoTest feature. These handheld tools can help us analyze roaming. A connect log is captured and documented along with other statistics such as signal strength, SNR, and retry rates. Being able to view this information in detail down to specific channel or even the BSSID helps us troubleshoot or analyze Wi-Fi with ease. Now, netAlly provides a validation survey capability. In this episode, we talk about AirMapper and how easy it is to use with a single handheld device. And we’re impressed with how the results can be uploaded to Link-Live and viewed on a web page. That could be our future of validation surveys. There’s a lot of potential there. Take a listen to this episode and let us know what your thoughts are on using netAlly EtherScope nXG or the AirCheck G2. Resources * Rowell’s blog reviewing 3 features of netAlly EtherScope nXG* Rowell’s video highlighting 3 features of the EtherScope nXG* netAlly

Power saving is a normal function of mobile devices. It’s required to conserve battery. In this episode, we summarize what we’ve read about Power Management from the 802.11 standard. Power save (PS) is a power management mode in which a station (STA) alternates between two states: * Awake: STA is fully powered* Dozing: STA is not able to transmit or receive and consumes very low power Stations may define their own power management states. For example, this is a configurable setting from a Wi-Fi scanner: * CAM – Constant Active Mode* Fast Power Save* MAX Power Save The Power Management Flag is located in the Frame Control Field located in the MAC header of the 802.11 frame: The Power Saving Flag is used by a STA to notify that it will go to sleep. That flag is sent within a Null Data Frame from the STA. The Null Data Frame contains no data at all but is used to specify whether the STA goes into Awake or Doze state. Null Data Frame sent when client is going to sleep Null Data Frames Power management flag When a STA goes into a doze state, traffic for the STA is buffered at the access point. How does the STA know there is data buffered for it? The Beacon frame includes a Traffic Indication Map (TIM) and Delivery TIM (DTIM) which tells the STA how often it should come out of doze state and check for buffered data. Traffic Indication Map The TIM contains a Partial Virtual Map and an Association ID for buffered data associated with a STA. The DTIM Count field indicates how many Beacon frames (including the current frame) appear before the next DTIM. A DTIM count of 0 indicates that the current TIM is a DTIM. The DTIM Period field indicates the number of beacon intervals between successive DTIMs. The Bitmap Control field contains the traffic indication virtual bitmap bit associated with an AID. This bit is set to 1 in TIM elements with a value of 0 in the DTIM Count field when one or more group addressed MSDUs/MMPDUs are buffered at the AP. Buffered data for multiple STAs Wireshark filters * Filter frames with the Power Management bit set to 1* wlan.fc.pwrmgt == 1* Filter null Data frames (null data + CF-Poll): * (wlan.fc.type == 2) && (wlan.fc.subtype == 4)* Filter beacon frame that indicates buffered data is available for doze STA: * (wlan.fc.type == 0) && (wlan.fc.subtype == 8) && (wlan.tim.partial_virtual_bitmap != 00) 802.11-2016 Sections * Section 6.3.2 – Power Management p.264* Section 9.2.4.1.7 – Power Management subfield p.642* Section 11.2 – Power Management (MLME) p.1599* Section 11.2.3 – Power management in a non-DMG infrastructure network p.1600* Figure 11-7 – Infrastructure power management operation (no PCF operating) p.1603 PCAP Files * Download here

Dynamic bandwidth operation occurs when a transmitter attempts to acquire the medium for a bonded channel but is only cleared to use a smaller channel width. For example, let’s consider an access point configured to serve devices with a 40 MHz channel width. A device would transmit an RTS for 40 MHz but the receiver (the AP) determines that only a 20 MHz channel can be used. Dynamic bandwidth operation utilizes Request to Send (RTS) and Clear to Send (CTS) frames. 802.11 has used RTS and CTS frames to clear the medium for transmissions and was typically used for hidden nodes. Every device, whether 802.11a/n/ac, was able to understand these frames and set their NAV based on the duration field. Additionally, the RTS and CTS frames were transmitted at lower data ratets. Then bonded channels came along. How would an 802.11a device understand another device that wanted to utilize a 40 MHz, 80 MHz, or 160 MHz channel width? A non-HT duplicate frame was transmitted at 802.11a PHY for all devices to hear and set their NAV. In 802.11ac, duplicate frames is used for bandwidth signaling. The RTS and CTS frames work to clear the channel that will be used by a transmitter. For example, I’m using channel 36 at 80 MHz wide and my primary channel is 36. An RTS would be duplicated on each of the 20 MHz channels, channel 40, 44, and 48. That is three additional RTS frames. This is to indicate the device would like to transmit using 80 MHz channel width. The receiver (AP in this case) would perform clear channel assessment (CCA) and send CTS frames for channels that are idle. If a channel is determined to be busy, then a CTS is not sent for that channel. Acquiring 80 MHz Channel Acquiring 40 MHz channel instead The Individual/Group bit would be set to 1 in the TA field which would make the address a bandwidth signaling transmitter address. I wanted to attempt to capture the non-HT duplicate frames. In my lab, I utilized two Ekahau Sidekicks on two separate laptops. Using Ekahau Capture, one Sidekick was set to capture on channel 149 and 153. The other on channel 157 and 161. Using Wireshark, I merged the two pcap files. Attached is what I was able to grab. Did I manage to capture the non-HT duplicate frames? I’m not sure. It’s the same duration, sent at a lower data rate, but I don’t see that the individual/group bit set to 1 in the TA field. What do you think? Resources * PCAP file

Meraki has been around for a long time. With over 508k customers, 2.5 million active networks, and in 190 countries, it’s about time there’s a certification around Meraki technologies. The Meraki-specific certification is the Cisco Meraki Solutions Specialist Certification. The exam is called Engineering Cisco Meraki Solutions, exam number 500-220 ECMS. Meraki’s ECMS certification covers everything across their product portfolio. Topics covered in Meraki’s certification include: * Wireless LAN* Switching* Security* SD-WAN,* Wireless WAN* Meraki Insight* Smart Cameras* Mobile Device Management You can catch all the objectives here. There are paid courses available from Cisco Meraki and they do recommend two different courses. The first is an introduction to Meraki and the 2nd has more technical deep dives. The first course is a 1-day course, ECMS1, and is meant for those just getting into Meraki. The second course is a 3-day course, ECMS2, and has many in-depth topics such as routing and switching. You could take the self-study route. Meraki has created a nice outline for their objectives mapped to content available online. Most of the content references Meraki documentation and others are videos. With the amount of topics covered, you might be asking if you need a lab environment for this. And yes, you will. Meraki created a Bill of Materials (BoM) for what you’ll need if you want to lab the whole thing. Here’s an example topology that Meraki has provided: What do you think of the Meraki certification? Is it something you’ll go after? Let us know in the comments below! Resources * https://meraki.cisco.com/blog/2020/10/announcing-the-cisco-meraki-solutions-specialist-certification/* https://www.cisco.com/c/en/us/training-events/training-certifications/certifications/specialist/meraki-solutions.html* https://www.cisco.com/c/dam/en_us/training-events/exams/topics/500-220-ecms.pdf*

Juniper is coming out with a new certification track for Mist under the Juniper certification portfolio. This track will be focused on Wi-Fi as well as anything Mist related. JNCIS-MistAI is the first official certification. Became available on September 28th 2020. JNCIA-MistAI will be coming before the end of the year. The new Juniper Mist AI-Driven Networks (MIST) 4-day training prepares yourself to pass the JNCIS-MistAI certification. JNCIS-MistAI Certification * No prerequisites for now. Might add JNCIA-MistAI when it becomes available.* JN0-450 in Pearson VUE* 90 minutes* 65 multiple-choice questions* $300USD A practice test is available on the Junos Genius: https://cloud.contentraven.com/junosgenius/learningpath-detail/3223/3/0/6 Previous & Free Mist Training Mist Master Certifications: https://courses.mist.com/dashboard (need to be logged in with your Mist account) * 0.5 WiFi Basics Course* 1 Mist Wi-Fi Certification* 2 Mist Location Certification* 3 Mist AI for IT Courses Links & Resources * Mist 4-day Training website: https://learningportal.juniper.net/juniper/user_activity_info.aspx?id=11460* Course Overview: Download Course Overview Flyer (PDF)* Mist AI Certification track details: https://www.juniper.net/us/en/training/certification/certification-tracks/mistai?tab=jncis-mistai* Junos Genius – Getting Started with Wi-Fi online training: https://cloud.contentraven.com/junosgenius/learningpath-detail/3009/3/0/1* Mist API Class: https://api-class.mist.com