My Journey in Wireless Networking: From Foundations to Expertise

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...

For the Wireless devices to efficiently discover and connect to available networks, there are two fundamental management frames that plays and important roles; Probe Request and Probe Response frames. Let's explore how these management frames work together to help your devices find and connect to wireless networks. What is Probe Request? Probe Requests are management frames sent by a Wireless Client device or a Station (STA) when searching for wireless networks. Think of them as your device calling out "Hello, is anyone there?" This frame serves two main purposes: Finding a specific network, you have connected in the past. Discovering all available networks in coverage area of the device. Types of Probe Requests The types of Probe Request is dictated by the length of the SSID field in the Probe Request. There are two types of Probe Requests:  Directed Probe Request Broadcast Probe Request    Directed Probe Requests: When your device is looking for a specific network, it ...

In the evolution of wireless networking protocols, one of the key advancements that has significantly improved efficiency and the throughput of the wireless client is the concept of frame aggregation. Traditional wireless frame transmission methods often incurred considerable overhead, with each frame requiring its own MAC Header and FCS. Frame aggregation addresses this challenge by allowing multiple data frames to be combined into a single, larger transmission. The Basics of Frame Aggregation Frame aggregation is a technique introduced in the 802.11n wireless standard and further enhanced in later versions like 802.11ac and 802.11ax. The underlying principle is to combine multiple MAC Protocol Data Units (MPDUs) into a single Physical Protocol Data Unit (PPDU) for transmission. Frame Aggregation Methods There are two primary types of frame aggregation: Aggregated-MSDU (A-MSDU): This method combines multiple MAC Service Data Units (MSDUs) into a single MPDU, reducing the overhead of ...

In the complex world of wireless networking, understanding the interactions between the MAC (Medium Access Control) and PHY (Physical) layers is crucial for comprehensive network analysis. The IEEE 802.11 standard implements these layers within the OSI model, providing a structured approach to wireless data transmissions. Before we begin our deep-dive into MAC and PHY layers, it is important to understand the OSI Layered Model and function of each layer. The OSI model comprises seven layers, each playing a critical role in data communication: Figure -1: OSI Layers and functions As seen in the image above, the IEEE 802.11 Standard operates in these Layer 1 (PHY) and Layer2 (MAC) Layers of the OSI Model.  Figure-2 MAC and PHY Layer Functions MAC Layer: The MAC layer serves as a critical component in WiFi networks, managing several essential functions: Key MAC Layer Responsibilities: 1. Frame Construction: Transforming raw data into standardized 802.11 frames 2. Medium Acces...

  In today's connected world, we're increasingly reliant on real-time applications like video calls, online gaming, and voice chat. But have you ever wondered why some calls are crystal clear while others break up, or why your video sometimes freezes during important meetings? The answer lies in a technology called Quality of Service (QoS), specifically 802.11 QoS for wireless networks. What is QoS and Why Should really You Care about it:  Quality of Service is like having a traffic management system for your network data. Just as an emergency vehicles get priority on the road over any other vehicle, certain types of network traffic need priority treatment to function properly. Without QoS, all network traffic is treated equally, which can lead to poor performance for time-sensitive applications such as voice and videos.  How we separate the Priority Queues: Network traffic generally falls into three main categories: 1.       Voice (high...