LOOP - Loopback Protocol
=========================

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        **What is LOOPBACK Interface?**

        The LOOPBACK Interface is a virtual network interface used by a host to communicate with itself.
        It is part of the Internet Protocol (IP) suite and is typically assigned the IP address 127.0.0.1 in IPv4 or ::1 in IPv6.

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        **Why is the LOOPBACK Interface Useful?**

        * Allows testing and development without requiring physical network hardware.
        * Used by applications and services to communicate internally on the same machine.
        * Helps in diagnosing network issues.
        * Ensures network software can function even without external connectivity.

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        **How it works?**

        * Application sends data to the loopback address.
        * IP stack recognizes the destination as local.
        * Data is looped back internally without leaving the host.
        * Receiving application on the same host gets the data.

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        **Where is LOOPBACK Interface used?**

        * Web servers (e.g., testing a site on http://127.0.0.1).
        * Database connections (e.g., connecting to localhost).
        * Software development and debugging.
        * Health checks for services running on the same machine.

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        **Which OSI layer does the LOOPBACK Interface operate at?**

        * The LOOPBACK Interface is part of the IP protocol, which operates at Layer 3 (Network Layer).
        * It handles IP addressing and routing, even though the route is internal.
        * It ensures logical addressing and packet delivery within the host.


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        Topics in this section,

                * :ref:`Learnings in this section <LOOP_step1>`

                * :ref:`Terminology <LOOP_step2>`

                * :ref:`Version Info <LOOP_step3>`

                * :ref:`LOOP Version&RFC Details <LOOP_step5>`

                * :ref:`LOOP Basic Setup on Ubuntu using IPv4 <LOOP_step19>`
                  
                * :ref:`LOOP Basic Setup on Ubuntu using IPv6 <LOOP_step20>`
                  
                * :ref:`LOOP Protocol Packet Details <LOOP_step6>`

                * :ref:`LOOP Usecases <LOOP_step7>`

                * :ref:`LOOP Basic Features <LOOP_step8>`
                    
                * :ref:`LOOP Feature : Local Communication <LOOP_step9>` 

                * :ref:`LOOP Feature : Virtual Interface <LOOP_step10>`

                * :ref:`LOOP Feature : Reserved Address Space <LOOP_step11>`  

                * :ref:`LOOP Feature : No External Routing <LOOP_step12>`  

                * :ref:`LOOP Feature : Protocol Testing <LOOP_step13>`

                * :ref:`LOOP Feature : Service Isolation <LOOP_step14>`

                * :ref:`LOOP Feature : IPV4 and IPV6 Support <LOOP_step15>`   

                * :ref:`LOOP Feature : Application Development <LOOP_step16>` 

                * :ref:`LOOP Feature : Performance Benchmarking <LOOP_step17>` 

                * :ref:`LOOP Feature : System Health Monitoring <LOOP_step18>`

                * :ref:`Reference links <LOOP_step21>`


.. _LOOP_step1:

.. tab-set::

    .. tab-item:: Learnings in this section

        * In this section, you are going to learn

.. _LOOP_step2:

.. tab-set::

    .. tab-item:: Terminology
        
       * Terminology


.. _LOOP_step3:

.. tab-set::

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


.. _LOOP_step5:

.. tab-set::

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

        
         .. csv-table:: 
               :file: ./LOOP/LOOP_RFC_Details.csv
               :widths: 10,10,10,30
               :header-rows: 1

.. _LOOP_step19:

.. tab-set::

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

       * Setup

 



.. _LOOP_step20:

.. tab-set::

   .. tab-item:: LOOP Basic Setup on Ubuntu using IPv6
   
      * Setup



.. _LOOP_step6:

.. tab-set::

    .. tab-item:: LOOP Protocol Packet Details
       
         **LOOPBACK Packet**

         .. csv-table:: 
                :file: ./LOOP/LOOP_Protocol_Packet_1.csv
                :widths: 10,20,30,10
                :header-rows: 1
        


.. _LOOP_step7:

.. tab-set::

    .. tab-item:: LOOP Usecases
        
        
         .. csv-table:: 
               :file: ./LOOP/LOOP_Usecases.csv
               :widths: 10,20,30
               :header-rows: 1

.. _LOOP_step8:

.. tab-set::

    .. tab-item:: LOOP Basic Features
    
         
         .. csv-table:: 
                  :file: ./LOOP/LOOP_Features.csv
                  :widths: 10,10,30
                  :header-rows: 1

.. _LOOP_step9:

.. tab-set::

    .. tab-item:: LOOP Feature : Local Communication

          **Local Communication - Testcases**

          .. csv-table:: 
                 :file: ./LOOP/LOOP_Feature-1_LocalCommunication_Testcase.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


   
.. _LOOP_step10:

.. tab-set::

    .. tab-item:: LOOP Feature : Virtual Interface

         **Virtual Interface - Testcases**

         .. csv-table:: 
                :file: ./LOOP/LOOP_Feature-2_VirtualInterface_Testcase.csv
                :widths: 10,10,30,20
                :header-rows: 1


.. _LOOP_step11:

.. tab-set::

    .. tab-item:: LOOP Feature : Reserved Address Space

        **Reserved Address Space - Testcases**

        .. csv-table:: 
                 :file: ./LOOP/LOOP_Feature-3_ReservedAddressSpace_Testcase.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


.. _LOOP_step12:

.. tab-set::

    .. tab-item:: LOOP Feature : No External Routing 

          **No External Routing - Testcases**

          .. csv-table:: 
                :file: ./LOOP/LOOP_Feature-4_NoExternalRouting_Testcase.csv
                :widths: 10,10,30,20
                :header-rows: 1



.. _LOOP_step13:

.. tab-set::

    .. tab-item:: LOOP Feature : Protocol Testing

         **Protocol Testing - Testcases**

         .. csv-table:: 
                 :file: ./LOOP/LOOP_Feature-5_ProtocolTesting_Testcase.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


 
.. _LOOP_step14:

.. tab-set::

    .. tab-item:: LOOP Feature : Service Isolation

         **Service Isolation - Testcases**

         .. csv-table:: 
                  :file: ./LOOP/LOOP_Feature-6_ServiceIsolation_Testcase.csv
                  :widths: 10,10,30,20
                  :header-rows: 1


.. _LOOP_step15:

.. tab-set::

    .. tab-item:: LOOP Feature : IPV4 and IPV6 Support
   
          **IPV4 and IPV6 - Testcases**

          .. csv-table:: 
                 :file: ./LOOP/LOOP_Feature-7_IPV4_and_IPV6_Support_Testcase.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


.. _LOOP_step16:

.. tab-set::

    .. tab-item:: LOOP Feature : Application Development

         **Application Development - Testcases**

         .. csv-table:: 
                 :file: ./LOOP/LOOP_Feature-8_Application_Development_Testcase.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


.. _LOOP_step17:

.. tab-set::

    .. tab-item:: LOOP Feature : Performance Benchmarking

        **Performance Benchmarking - Testcases**

        .. csv-table::
                :file: ./LOOP/LOOP_Feature-9_Performance_Benchmarking_Testcase.csv
                :widths: 10,10,30,20
                :header-rows: 1

.. _LOOP_step18:

.. tab-set::

    .. tab-item:: LOOP Feature : System Health Monitoring

        **System Health Monitoring - Testcases**

        .. csv-table::
                :file: ./LOOP/LOOP_Feature-10_System_Health_Monitoring_Testcase.csv
                :widths: 10,10,30,20
                :header-rows: 1


.. _LOOP_step21:

.. tab-set::

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