NVGRE - Network Virtualization using GRE
===========================================

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        **What is NVGRE?**

        NVGRE (Network Virtualization using Generic Routing Encapsulation) is a network virtualization protocol that encapsulates Layer 2 Ethernet frames within GRE (Generic Routing Encapsulation) tunnels over an IP network.

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        **Why is NVGRE useful?**

        NVGRE enables scalable multi-tenant networks by allowing multiple isolated virtual networks to coexist over a shared physical infrastructure. It overcomes VLAN scalability limits and supports cloud computing environments.

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        **How it works?**

        NVGRE wraps Layer 2 Ethernet frames with a GRE header and transports them over an IP network. Each virtual network is identified using a 24-bit Tenant Network Identifier (TNI), enabling traffic isolation and scalability.

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        **Where is NVGRE used?**

        NVGRE is mainly used in data centers and enterprise cloud infrastructures for virtual network overlays, especially in Microsoft-based environments like Hyper-V and Windows Server.

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        **Which OSI layer does this protocol belong to?**

        NVGRE primarily operates at Layer 2 (Data Link Layer) for encapsulation, but is transported across Layer 3 (Network Layer) using GRE.

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        **Is NVGRE Windows specific?**

        NVGRE is heavily supported in Microsoft environments (e.g., Hyper-V, System Center), but it is not exclusive to Windows. However, adoption outside Windows is limited.

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        **Is NVGRE Linux specific?**

        No, NVGRE is not Linux specific, but Linux can support it through GRE tunneling and software-defined networking tools, although it is less common than VXLAN in Linux-based systems.

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        **Which Transport Protocol is used by NVGRE?**

        NVGRE uses **GRE (Generic Routing Encapsulation)** as the transport protocol, which is an IP protocol (not TCP/UDP-based).

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        **Which Port is used by NVGRE?**

        NVGRE does **not use a specific port number**. It uses IP protocol number **47** for GRE encapsulation.

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        **Is NVGRE using Client server model?**

        No, NVGRE does not use a client-server model. It is a tunneling protocol used for encapsulating and transporting network traffic across virtualized environments.

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        Topics in this section,

                * :ref:`Learnings in this section <NVGRE_step1>`

                * :ref:`Terminology <NVGRE_step2>`

                * :ref:`Version Info <NVGRE_step3>`

                * :ref:`NVGRE Version&IEEE Details <NVGRE_step5>`

                * :ref:`NVGRE Basic Setup on Ubuntu using IPv4 <NVGRE_step18>`

                * :ref:`NVGRE Basic Setup on Ubuntu using IPv6 <NVGRE_step19>`

                * :ref:`NVGRE Protocol Packet Details <NVGRE_step6>`

                * :ref:`NVGRE Usecases <NVGRE_step7>`

                * :ref:`NVGRE Basic Features <NVGRE_step8>`
                    
                * :ref:`Reference links <NVGRE_step17>`


.. _NVGRE_step1:

.. tab-set::

    .. tab-item:: Learnings in this section

        * In this section, you are going to learn

.. _NVGRE_step2:

.. tab-set::

    .. tab-item:: Terminology
        
       * Terminology


.. _NVGRE_step3:

.. tab-set::

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

.. _NVGRE_step5:

.. tab-set::

    .. tab-item:: NVGRE Version&RFC Details

        * rfc details

.. _NVGRE_step18:

.. tab-set::

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

       * setup

.. _NVGRE_step19:

.. tab-set::
  
   .. tab-item:: NVGRE Basic Setup on Ubuntu using IPv6

     * setup
       
.. _NVGRE_step6:

.. tab-set::

    .. tab-item:: NVGRE Protocol Packet Details

        * packet details
       


.. _NVGRE_step7:

.. tab-set::

    .. tab-item:: NVGRE Usecases

       * usecases
        
        

.. _NVGRE_step8:

.. tab-set::

    .. tab-item:: NVGRE Basic Features
    
        * features 



.. _NVGRE_step17:

.. tab-set::

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