802.11a Packet Formats
==========================


.. panels::
    :container: container pb-4
    :column: col-lg-12 p-2
    :card: shadow

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the general structure of an 802.11a packet?**

        An 802.11a packet consists of a preamble, header, payload (data), and frame check sequence (FCS).

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What types of frames exist in 802.11a?**

        There are three main frame types: Management, Control, and Data frames.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the purpose of the preamble in 802.11a packets?**

        The preamble allows the receiver to synchronize timing and frequency before decoding the actual data.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What modulation is used in the preamble of 802.11a?**

        The preamble uses BPSK modulation at 6 Mbps to ensure robust synchronization.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is contained in the PLCP header?**

        The Physical Layer Convergence Protocol (PLCP) header carries information about the length and data rate of the payload.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **How long is the PLCP header in 802.11a?**

        The PLCP header is 24 microseconds long, consisting of SIGNAL, SERVICE, LENGTH, and CRC fields.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What does the SIGNAL field specify in the PLCP header?**

        It indicates the data rate at which the payload is transmitted.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the purpose of the SERVICE field in the PLCP header?**

        It carries information about additional features or future use, usually set to zero in 802.11a.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What does the LENGTH field represent in the PLCP header?**

        The LENGTH field specifies the number of microseconds the payload transmission will last.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the role of the CRC in the PLCP header?**

        The CRC checks the integrity of the PLCP header to ensure it is received correctly.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the MAC header in 802.11a packets?**

        The MAC header contains frame control, duration, address fields, sequence control, and QoS control if used.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **How many address fields does the MAC header have?**

        Typically, there are up to four address fields, depending on the frame type and whether it is infrastructure or ad hoc mode.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the Frame Control field in the MAC header?**

        It defines the frame type, subtype, protocol version, and control flags like retry, power management, and more.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What does the Duration/ID field indicate?**

        It contains the time in microseconds the channel will be reserved for the transmission or contains association ID for power management.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the Sequence Control field used for?**

        It helps in detecting duplicate frames and ordering frames correctly via sequence numbers.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the purpose of the Frame Body (payload)?**

        It carries the actual data or management/control information being transmitted.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **What is the Frame Check Sequence (FCS)?**

        A 32-bit CRC used to detect errors in the entire MAC frame.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **How does 802.11a packet format support high data rates?**

        Through the use of OFDM modulation, variable data rates in the SIGNAL field, and efficient MAC framing.

    .. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        **Are management and control frames formatted differently from data frames?**

        Yes, management and control frames have specific frame bodies and may omit some MAC header fields for efficiency.

.. panels::
        :container: container pb-4
        :column: col-lg-12 p-2
        :card: shadow

        Topics in this section,

                * :ref:`Learnings in this section <packet_formats_step1>`

                * :ref:`Terminology <packet_formats_step2>`

                * :ref:`Version Info <packet_formats_step3>`

                * :ref:`packet_formats Basic Setup on Ubuntu using IPv4 <packet_formats_step18>`

                * :ref:`Reference links <packet_formats_step17>`

.. _packet_formats_step1:

.. tab-set::

    .. tab-item:: Learnings in this section

        * In this section, you are going to learn

.. _packet_formats_step2:

.. tab-set::

    .. tab-item:: Terminology
        
       * Terminology


.. _packet_formats_step3:

.. tab-set::

    .. tab-item:: Version Info
    
         * Version Info


.. _packet_formats_step18:

.. tab-set::

    .. tab-item:: packet_formats Basic Setup on Ubuntu using IPv4

       * setup


.. _packet_formats_step17:

.. tab-set::

    .. tab-item:: Reference links
     
       * Reference links