Introduction DFS is not a new topic and anyone who has a little bit of knowledge of RF or WiFi has some sort of understanding regarding DFS or DFS channels etc. There are a lot of blogs and posts on the topic. Whenever I read a blog or watch a video on DFS topic most of people only speak about radar and radar channels. so over time, everyone thinks about DFS as radar and radar detection only. However, it’s not TRUE! (please don’t hate me for saying this). A common misconception is that DFS is solely concerned with radar detection. In reality, DFS plays a broader role in band management, encomp ..read more

WLAN Topologies AKA Service Sets: I would like to talk about WLAN topologies or service sets which are not difficult to but very important to understand. 802.11 defines different topologies or service sets. BSS (Basic service set) ESS (Extended service set) IBSS (Independent basic service set) MBSS (Mesh basic service set) QBSS (QOS basic service set) now look at few other abbreviations you might come across when we are talking about service sets. Station (STA) any device with WiFi radio, it could access point or your laptop, mobile etc BSSID (Basic service set ID) BSA (Basic service area ..read more

My plan was to explain DL MU-OFDMA which includes trigger frames, CTS, MU-PPDU, and ACK  in one post but that would become boring. so I have decided to split it into 2 posts.  1- MU-Trigger frame 2- MU-PPDU In this post, we will only look at MU-Trigger frame.  Note: PCAP is taken with help of raspberry Pi4 and intel AX210 card The scenario includes multiple clients and an 802.11ax hub Frame breakdown is done with the help of IEEE 802.11ax draft 2021 Let’s start: MU-OFDMA transmission can start with an MU-Trigger frame and then CTS from each station or AP can send clear to send ..read more

I would like to write this post specifically for beginners who are trying to understand that what is a protocol analyser or what are the options available specific to Wi-Fi troubleshooting. First question what is protocol analyser Why we need it What options are available to capture WLAN traffic How we can use it for our benefit such as troubleshooting or to test whether your network is performing as it has been configure what is protocol analyser: Protocol analysers are the tools software or hardware capable of connecting to a Wired or Wireless network  in ord ..read more

MU-PPDU: We have explored the first part (MU-trigger frame) of MU-OFDMA transmission already in a different post. Once the following conditions are met: MU-RTS trigger frame sent by the AP CTS response from the devices or AP sends CTS Now AP can start sending the data. At this point, we should expect MU PPDU’s from AP to client devices with AID’s in the trigger frame. Once AP receives ACK from the client devices this transaction is completed. Figure1: (MU-OFDMA transmission with MU-RTS/CTS and Nav setting) Before we start going through the MU-PPDU on Wireshark. It’s important to know there ..read more

Wireless Global Congress: WIFI revolution where every operator is chipping in.  WBA is the leading event on next gen service opportunities for wireless carriers and connected cities ecosystems. WBA works closely with mobile networks and broadband service providers. Wireless broadband alliance resolve business issues and enable collaborative opportunities for service providers, enterprises and cities, that enable them to enhance the customer experience on Wi-Fi and significant adjacent technologies. Why WIFI events are important: Question is why should we bother about these events an ..read more

There is a lot of hype going around 5G since its announced, there is discussion going on social media whether 5G is going to impact Wi-Fi. The 5G standard promises mobile connectivity at high speed. Theoretically it can give faster and better user experience. So, I decided to write what I think about this whole situation. Whether 5G will take over Wi-Fi and Wi-Fi will just disappear or 5G will improve performance and will work alongside Wi-Fi? I think we must see this from practicality point of view. Theoretically it might be possible to give every device high speed connection, but question is ..read more

Wireshark has two filtering languages: One used when capturing packets, and one used when displaying packets. These display filters are already been shared by clear to send . It was shared as image file so I decided add different filters together and type here so people can just copy paste the filters instead having to type again themselves. Wireshark Display Filters related management traffic: wireshark display filters: management frames wlan.fc.type == 0 all management frames       wlan.fc.type_subtype == 0 association requests   wlan.fc.type_subtype ..read more

I was thinking to write about the 4-way handshake and started to think that from where I should start writing. Shall I just describe 4-way handshake which can be found everywhere on the web or shall I do a deep dive?  Reason for me to write is to make it easier to understand for non WiFi people who can just read and understand because sometimes different terminologies used in this process can be confusing. So, let’s start with… What is 4-way Handshake: The 4-way handshake is the process of exchanging 4 messages between an access point (authenticator) and the client device (supplicant) to ..read more

Today I would like to take the opportunity to write about inverse square law. What is inverse square law and why it’s important for us as Wi-Fi Engineers to understand. Its important to understand that how RF behaves when distance increases. I will start with light example which is easy to understand, and it work same way as RF. Characteristics of the light is when it comes out of the source the intensity will start decreasing very fast. Let’s suppose we place a light bulb or say antenna in WLAN scenario and want to test intensity of signal or light on the one cell of the football highlighted ..read more