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wifi network architecture

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Wi-Fi, short for Wireless Fidelity, refers to a set of wireless networking technologies that allow devices to communicate over a local area network (LAN) without the need for physical cables. Wi-Fi is based on the IEEE 802.11 family of standards, which define the specifications for implementing wireless local area networking (WLAN) communication.

Here is a detailed technical explanation of the Wi-Fi network architecture:

  1. Physical Layer (PHY):
    • The physical layer is responsible for the transmission and reception of raw radio frequency signals.
    • It defines how data is modulated onto radio waves and transmitted over the air.
    • Different standards within the 802.11 family (such as 802.11b, 802.11g, 802.11n, 802.11ac, and 802.11ax) operate at different frequency bands and use various modulation techniques to achieve different data rates.
  2. Medium Access Control (MAC) Layer:
    • The MAC layer is responsible for controlling access to the physical medium (the airwaves) and managing the transmission of data frames between devices.
    • It uses the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol to avoid collisions in the wireless medium.
    • The MAC layer is also responsible for frame acknowledgment, retransmission, and handling different network topologies (ad-hoc or infrastructure mode).
  3. Service Set Identifier (SSID):
    • The SSID is a unique identifier assigned to a Wi-Fi network. It allows devices to distinguish between different wireless networks.
    • When a device wants to connect to a Wi-Fi network, it scans for available SSIDs and selects the desired network.
  4. Basic Service Set (BSS):
    • The BSS is the basic building block of a Wi-Fi network and consists of one or more stations (devices) communicating with each other.
    • In infrastructure mode, a BSS includes one access point (AP) and one or more associated stations.
    • In ad-hoc mode, a BSS is formed directly between devices without the need for an access point.
  5. Extended Service Set (ESS):
    • An ESS is a set of interconnected BSSs. It allows users to roam seamlessly between different access points within the same network without losing connectivity.
    • The devices in an ESS share the same SSID and are part of the same logical network.
  6. Distribution System (DS):
    • The DS connects multiple BSSs and facilitates communication between devices in different BSSs.
    • In infrastructure mode, the DS is typically implemented using wired Ethernet connections, allowing wireless clients to communicate with devices on the wired network.
  7. Wireless Distribution System (WDS):
    • WDS is a protocol that allows the interconnection of access points wirelessly, creating a bridge between different parts of a network without the need for physical cabling.
    • It is commonly used for extending network coverage and bridging between wired and wireless segments.
  8. Security Protocols:
    • Wi-Fi networks use various security protocols, such as WEP, WPA, and WPA2/WPA3, to encrypt and secure data transmissions.
    • Encryption keys are used to protect the confidentiality and integrity of the data exchanged between devices on the network.