Header Structure
====================

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        **What is IPv6 Header Structure?**

        The IPv6 Header Structure is a fixed-length 40-byte header at the start of every IPv6 packet. It contains essential information for routing and delivery, such as version, traffic class, flow label, payload length, next header, hop limit, and source/destination IP addresses.

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        **Why is IPv6 Header Structure useful?**

        It simplifies packet processing by routers with a streamlined fixed format, removing fields like checksum and fragmentation from the base header. This leads to faster routing and improved network performance.

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        **How does IPv6 Header Structure work?**

        The header carries all necessary information to route packets efficiently. The Flow Label helps with traffic prioritization, the Next Header indicates the type of header following the base header, and the Hop Limit field prevents infinite loops in routing.

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        **Where is IPv6 Header Structure used?**

        It is included in every IPv6 packet transmitted over IP networks, supporting modern internet applications, enterprise networks, and future-proof communications with larger address spaces.

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        **Which OSI layer does IPv6 Header Structure belong to?**

        IPv6 Header Structure operates at the **Network Layer (Layer 3)** of the OSI model, responsible for logical addressing and routing between networks.

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        **Is IPv6 Header Structure Windows specific?**

        No, IPv6 is a platform-independent protocol, and its header structure is implemented on all major operating systems including Windows, Linux, and macOS.

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        **Is IPv6 Header Structure Linux specific?**

        No, IPv6 header processing is standard across all networking stacks. Linux provides tools like `ip` and `tcpdump` to view and manipulate IPv6 headers, but the protocol itself is universal.

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        **Which Transport Protocol is used by IPv6 Header Structure?**

        IPv6 supports transport protocols such as **TCP**, **UDP**, **ICMPv6**, and others. The Next Header field specifies the transport or extension header following the base IPv6 header.

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        **Which Port is used by IPv6 Header Structure?**

        IPv6 header itself does **not include port numbers**; ports belong to transport layer protocols like TCP and UDP. The IPv6 header directs packets to the appropriate host before transport layer processing.

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        **Is IPv6 Header Structure using client-server model?**

        The IPv6 header is agnostic to communication models; it supports client-server, peer-to-peer, multicast, and any IP-based communication by enabling packet delivery between IPv6 addresses.

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        Topics in this section,

                * :ref:`Learnings in this section <Header_Structure_step1>`

                * :ref:`Terminology <Header_Structure_step2>`

                * :ref:`Version Info <Header_Structure_step3>`

                * :ref:`Header Structure Basic Setup on Ubuntu using IPv6 <Header_Structure_step18>`
                
                * :ref:`Reference links <Header_Structure_step17>`

.. _Header_Structure_step1:

.. tab-set::

    .. tab-item:: Learnings in this section

        * In this section, you are going to learn

.. _Header_Structure_step2:

.. tab-set::

    .. tab-item:: Terminology
        
       * Terminology


.. _Header_Structure_step3:

.. tab-set::

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


.. _Header_Structure_step18:

.. tab-set::

   .. tab-item:: Header Structure Basic Setup on Ubuntu using IPv6

     * setup
 
.. _Header_Structure_step17:

.. tab-set::

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