My Journey in Wireless Networking: From Foundations to Expertise

In the world of wireless networking, collision avoidance is a critical challenge. Unlike wired networks where collisions can be detected, wireless networks must employ mechanisms to prevent collisions before they happen. One of the most important mechanisms in IEEE 802.11 (WiFi) networks is the Request to Send/Clear to Send (RTS/CTS) protocol. Let's dive into how this solution works and why it's essential for efficient wireless communications. The Hidden Node Problem Before understanding RTS/CTS, we need to understand the problem it solves: the hidden node problem. Imagine three wireless stations (STAs) - A, B, and C. Station-B can communicate with both A and C, but A and C are out of range of each other. If station A is transmitting to B, station C has no way of knowing this and might also try to transmit to B simultaneously, causing a collision at B. This is the "hidden node" problem - where some nodes in a network are invisible to each other but can still interfere...

 In the rapidly increasing adaption of Internet of Things (IoT), understanding  the basics network performance metrics is crucial for building reliable and efficient systems. Two fundamental metrics that play a n important role in the IOT Device communication are the Received Signal Strength Indicator (RSSI) and Link Quality Indication (LQI). Let's dive deep into what these metrics mean and why they matter for IoT implementations. Received Signal Strength Indicator (RSSI) RSSI serves as a fundamental measurement of RF power received by a wireless device. What makes RSSI particularly interesting is that it measures all RF power in a channel, regardless of the source. This means it captures: Signals from IEEE802.15.4 transmitters Interference from Bluetooth devices WiFi signals Background radiations This comprehensive measurement makes RSSI an essential tool for Clear Channel Assessment (CCA), helping devices determine if a channel is free befo...

 The ZigBee device onboarding process represents a critical workflow in IoT device management, facilitating secure and reliable connection establishment between end devices and the network infrastructure. This document outlines the systematic approach to ZigBee device onboarding:  Lets understand the Key Component of an IOT infrastructure:  End Node/End Device Represents any ZigBee-compliant IoT device, sensor, or actuator Includes various device types such as: Smart lighting systems Security devices (door locks) Environmental sensors Access Point (AP)/Gateway Comprises an embedded IoT chipset integrated into the AP Alternatively implemented as a USB module Co-ordinator (IoT Controller) Implemented as Ruckus IoT Control Manages device onboarding operations Co-ordinates MQTT traffic flow between the End notes and 3rd Party Integrations IOT Device Onboarding Process Flow Phase 1: Discovery Initiation Device Discovery State Activation Implementation varies ...

In the world of wireless network security, hiding your SSID might seem like an easy way to protect your WiFi network from unauthorized access. This approach of hiding an SSID provides a little more than a false sense of security. In my recent experience of debugging an issue with where random users could see these Hidden SSID’s, lead me to write a blog about why I personally believe it is not a great approach and I am open to opinions. Let’s explore how Hidden SSIDs Works and understand with a real world example!  When you configure your Access Points to hide the SSID/WLAN, you are essentially telling it to stop broadcasting the SSID name in the beacon frames. Under normal circumstances, An AP would periodically broadcast beacon frames containing, SSID Name, Channel, Security Capabilities etc. that helps a STA to choose among the broadcast SSID and associate to it. With Hidden SSID enabled, the AP continues to broadcast beacon frames but removes the network/SSID filed for the resp...

As a part of 802.11 Supplicant and Authenticator handshake, A STA must perform Authentication with the Access Point. This Authentication is often confused with some sort of security handshake or user authentication, which it is completely not! So what it is in reality? Operating at the link level, these frames are fundamental components of the Open System authentication method, involving a two-message exchange process that ensures proper network access control. Authentication Message Exchange: The authentication process begins when an unauthenticated and unassociated Station, generates the first authentication frame. In this initial frame, the station includes its MAC address in both the Source Address (SA) and Transmitter Address (TA) fields, while the target BSSID is specified in the Destination Address (DA) and Receiver Address (RA) fields. Wireshark Filter : "wlan.fc.type_subtype eq 11" Access point responds with a second authentication frame. This response reverses the a...

 When your smartphone or laptop (known as a STA - Station) connects to a WiFi access point (AP), it goes through a sequence of steps. This process ensures both devices can communicate effectively and securely. After successful open Authentication Phase, the Station goes through the Association Phase Association Request The Station device sends an Association Request frame to the SSID it is interested to connect with containing following information: Capability Information: What your device can do Listen Interval: How often it will wake up to check for messages. It is measured in the units of Beacon Interval  Network Name (SSID): The WiFi network it wants to join Supported Rates: What data rates station can handle If the capabilities match those of the Access Point the STA is connecting to, the STA will become associated to the Access Point and be the part of the BSS. Following Capture shows parameters of Association Request: Association Response Upon receiving Association ...

Pseudo headers is representation of PHY information that is displayed with the captured frames from a Protocol analyzer(Wireshark). It play a crucial role in providing detailed information about signal strength, SNR, Data rates, Channels etc. While troubleshooting an issue, this information provides a detailed information about frame transmission and reception characteristics. When looking at any Wireless Captures, you must have seen the Radiotap Header which is the most well-known example of a Pseudo Header. Lets explore some of the important fields of Radiotap header:   Header length : Duration of wireless frame is derived from the PHY Header length field. It determines how long it will take to transmit the PPDU. Timestamp : It is the current timestamp of the packet and it helps STA to synchronize its timing with the Access Point. Flags:  The flags shows different PPDU related flags such as, Preamble Type: Short/Long, Frame Check Sequence (FCS) handling, Fragmentation...