Video Description

WIFI- Wireless fidelity

  • LAN Protocol

  • IEEE 802.11

  • Standards: a,b,g, and n

    • Frequency

    • Speed

  • Works in ISM band

  • Uses 2.4 GHz and 5GHz

  • Frequency band divided into channels

  • Governed by WiFi Alliance

802.11 Standard- WLAN standard

  • Uses air as transmission media

  • Concerned with the 2 lower layers of the OSI model

  • Data link layer

    • Logical link control (LLC)

    • Medium access control (MAC)

  • Physical layer

    • Physical layer convergence procedure (PLCP)

    • Physical medium dependent (PMD)

Infrastructure vs Ad-Hoc Modes- Infrastructure

  • Uses access point

  • Star topology

  • More commonly used

  • Ad-Hoc

    • Direct communication

    • Exists for short period

    • Suitable for meetings and conferences

    • More flexible in setup

    • Point-to-point

SSID- Service Set Identifier

  • Used to identify wireless LAN

  • Can be broadcasted or hidden

  • Length: 32 alphanumeric characters

  • Can be composed of several access points

  • Single access point can connect to several SSIDs

CSMA/CA- Carrier Sense Multiple Access Collision Avoidance

  • Uses request to send RTS and clear to send CTS to avoid collisions

  • Possibility of collision still exists

  • Lead to slower performance

  • Recovered by resending

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