IPv4 Addressing
=========================

.. toctree::
   :maxdepth: 1
   :hidden:
   :includehidden:

   IPv4_Addressing/Anycast_Addressing_IPv4
   IPv4_Addressing/Broadcast_Addressing
   IPv4_Addressing/CIDR
   IPv4_Addressing/Classful_Addressing
   IPv4_Addressing/Multicast_Addressing
   IPv4_Addressing/NAT
   IPv4_Addressing/Subnetting_IPv4
   IPv4_Addressing/Unicast_Addressing


This section introduces various IPv4 addressing techniques used in IP networks. These methods determine how IP packets are delivered—from one-to-one, one-to-many, or even one-to-nearest. They are fundamental to designing efficient and secure IP networks.

.. list-table::
   :widths: 25 60 15
   :header-rows: 1

   * - Addressing Type
     - Description
     - Use Case
   * - Anycast
     - One-to-nearest delivery. Packets go to the closest destination with the shared IP.
     - Load balancing, DNS, CDN nodes.
   * - Broadcast
     - One-to-all delivery within a subnet. IPv4 supports this.
     - ARP, DHCP discovery.
   * - CIDR
     - Classless subnetting with VLSM. Replaces classful addressing.
     - Route aggregation, modern IP allocation.
   * - Classful
     - Legacy method using fixed IP blocks (A, B, C, etc.).
     - Historical networks.
   * - Multicast
     - One-to-many group communication.
     - Streaming, OSPF, conferencing.
   * - NAT
     - Private-to-public IP mapping.
     - IPv4 conservation, home routers.
   * - Subnetting
     - Divides networks into smaller subnets.
     - IP management, routing control.
   * - Unicast
     - One-to-one delivery.
     - Browsing, file transfers, email.

.. tab-set::

   .. tab-item:: Anycast

      **RFC:** RFC 1546

      **Main Features:**

      - One-to-nearest delivery based on routing metrics.
      - Multiple hosts share the same IP.

      **Use Cases:**

      - DNS root servers  
      - Content delivery networks (CDNs)  
      - Load balancing in routing

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

         **Learn More About Anycast:**

         * :ref:`Learnings in this section <Anycast_Addressing_step1>`

         * :ref:`Terminology <Anycast_Addressing_step2>`

         * :ref:`Version Info <Anycast_Addressing_step3>`

         * :ref:`Anycast_Addressing FAQs <Anycast_Addressing_step4>`

         * :ref:`Anycast_Addressing Version&IEEE Details <Anycast_Addressing_step5>`

         * :ref:`Anycast_Addressing Basic Setup on Ubuntu using IPv4 <Anycast_Addressing_step18>`

         * :ref:`Anycast_Addressing Basic Setup on Ubuntu using IPv6 <Anycast_Addressing_step19>`

         * :ref:`Anycast_Addressing Protocol Packet Details <Anycast_Addressing_step6>`

         * :ref:`Anycast_Addressing Usecases <Anycast_Addressing_step7>`

         * :ref:`Anycast_Addressing Basic Features <Anycast_Addressing_step8>`

         * :ref:`Reference links <Anycast_Addressing_step17>`

         .. button-link:: ./IPv4_Addressing/Anycast_Addressing_IPv4.html
            :color: primary
            :shadow:
            :expand:

            Jump to "Anycast"

.. tab-set::

   .. tab-item:: Broadcast

      **RFC:** RFC 919, RFC 922

      **Main Features:**

      - One-to-all within subnet.
      - IPv4 only; IPv6 does not support broadcast.

      **Use Cases:**

      - ARP discovery  
      - DHCPDISCOVER messages

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

         **Learn More About Broadcast:**

         * :ref:`Learnings in this section <Broadcast_Addessing_step1>`

         * :ref:`Terminology <Broadcast_Addessing_step2>`

         * :ref:`Version Info <Broadcast_Addessing_step3>`

         * :ref:`Broadcast_Addessing FAQs <Broadcast_Addessing_step4>`

         * :ref:`Broadcast_Addessing Version&IEEE Details <Broadcast_Addessing_step5>`

         * :ref:`Broadcast_Addessing Basic Setup on Ubuntu using IPv4 <Broadcast_Addessing_step18>`

         * :ref:`Broadcast_Addessing Basic Setup on Ubuntu using IPv6 <Broadcast_Addessing_step19>`

         * :ref:`Broadcast_Addessing Protocol Packet Details <Broadcast_Addessing_step6>`

         * :ref:`Broadcast_Addessing Usecases <Broadcast_Addessing_step7>`

         * :ref:`Broadcast_Addessing Basic Features <Broadcast_Addessing_step8>`

         * :ref:`Reference links <Broadcast_Addessing_step17>`

         .. button-link:: ./IPv4_Addressing/Broadcast_Addressing.html
            :color: primary
            :shadow:
            :expand:

            Jump to "Broadcast"
            
.. tab-set::

   .. tab-item:: CIDR

      **RFC:** RFC 4632

      **Main Features:**

      - Replaces classful addressing.
      - Allows subnetting with variable-length subnet masks.

      **Use Cases:**

      - Route summarization  
      - IP space efficiency in ISPs

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

         **Learn More About CIDR:**

         * :ref:`Learnings in this section <RADIUS_step1>`

         * :ref:`Terminology <RADIUS_step2>`

         * :ref:`Version Info <RADIUS_step3>`

         * :ref:`RADIUS FAQs <RADIUS_step4>`

         * :ref:`RADIUS Version&IEEE Details <RADIUS_step5>`

         * :ref:`RADIUS Basic Setup on Ubuntu using IPv4 <RADIUS_step18>`

         * :ref:`RADIUS Basic Setup on Ubuntu using IPv6 <RADIUS_step19>`

         * :ref:`RADIUS Protocol Packet Details <RADIUS_step6>`

         * :ref:`RADIUS Usecases <RADIUS_step7>`

         * :ref:`RADIUS Basic Features <RADIUS_step8>`

         * :ref:`Reference links <RADIUS_step17>`

         .. button-link:: ./IPv4_Addressing/CIDR.html
            :color: primary
            :shadow:
            :expand:

            Jump to "CIDR"

.. tab-set::

   .. tab-item:: Classful

      **RFC:** RFC 791 (conceptual, now obsolete)

      **Main Features:**

      - Divides address space into Class A, B, C, etc.
      - Lacks flexibility, poor address utilization.

      **Use Cases:**

      - Legacy IP networks  
      - Educational/historical references

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

         **Learn More About Classful Addressing:**

         * :ref:`Learnings in this section <RADIUS_step1>`

         * :ref:`Terminology <RADIUS_step2>`

         * :ref:`Version Info <RADIUS_step3>`

         * :ref:`RADIUS FAQs <RADIUS_step4>`

         * :ref:`RADIUS Version&IEEE Details <RADIUS_step5>`

         * :ref:`RADIUS Basic Setup on Ubuntu using IPv4 <RADIUS_step18>`

         * :ref:`RADIUS Basic Setup on Ubuntu using IPv6 <RADIUS_step19>`

         * :ref:`RADIUS Protocol Packet Details <RADIUS_step6>`

         * :ref:`RADIUS Usecases <RADIUS_step7>`

         * :ref:`RADIUS Basic Features <RADIUS_step8>`

         * :ref:`Reference links <RADIUS_step17>`

         .. button-link:: ./IPv4_Addressing/Classful_Addressing.html
            :color: primary
            :shadow:
            :expand:

            Jump to "Classful"

.. tab-set::

   .. tab-item:: Multicast

      **RFC:** RFC 1112, RFC 5771

      **Main Features:**

      - One-to-many group delivery.
      - More efficient than broadcast for large-scale data.

      **Use Cases:**

      - IPTV  
      - Video conferencing  
      - OSPF, PIM routing updates

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

         **Learn More About Multicast:**

          * :ref:`Learnings in this section <Multicast_Addressing_step1>`

          * :ref:`Terminology <Multicast_Addressing_step2>`

          * :ref:`Version Info <Multicast_Addressing_step3>`

          * :ref:`Multicast_Addressing FAQs <RADIUS_step4>`

          * :ref:`Multicast_Addressing Version&IEEE Details <RADIUS_step5>`

          * :ref:`Multicast_Addressing Basic Setup on Ubuntu using IPv4 <Multicast_Addressing_step18>`

          * :ref:`Multicast_Addressing Basic Setup on Ubuntu using IPv6 <Multicast_Addressing_step19>`

          * :ref:`Multicast_Addressing Protocol Packet Details <Multicast_Addressing_step6>`

          * :ref:`Multicast_Addressing Usecases <Multicast_Addressing_step7>`

          * :ref:`Multicast_Addressing Basic Features <Multicast_Addressing_step8>`

          * :ref:`Reference links <Multicast_Addressing_step17>`

          .. button-link:: ./IPv4_Addressing/Multicast_Addressing.html
            :color: primary
            :shadow:
            :expand:

            Jump to "Multicast"

.. tab-set::

   .. tab-item:: NAT

      **RFC:** RFC 3022

      **Main Features:**

      - Translates private IP to public.
      - Extends IPv4 usability and adds a security layer.

      **Use Cases:**

      - Home/enterprise firewalls  
      - ISPs managing limited IPv4 blocks

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

         **Learn More About NAT:**

         * :ref:`Learnings in this section <NAT_step1>`

         * :ref:`Terminology <NAT_step2>`

         * :ref:`Version Info <NAT_step3>`

         * :ref:`NAT Version&RFC Details <NAT_step5>`

         * :ref:`NAT Basic Setup on Ubuntu using IPv4 <NAT_step16>`

         * :ref:`NAT Basic Setup on Ubuntu using IPv6 <NAT_step17>`

         * :ref:`NAT Usecases <NAT_step6>`

         * :ref:`NAT Basic Features <NAT_step7>`

         * :ref:`NAT Feature : IP Address Translation <NAT_step8>`

         * :ref:`NAT Feature : Port Address Translation (PAT) <NAT_step9>`

         * :ref:`NAT Feature : Conserves IPv4 Addresses <NAT_step10>`

         * :ref:`NAT Feature : Enhances Network Security <NAT_step11>`

         * :ref:`NAT Feature : Supports Multiple NAT Types <NAT_step12>`

         * :ref:`NAT Feature : Protocol-Aware Behavior <NAT_step13>`

         * :ref:`NAT Feature : Enables Internet Access for Private Networks <NAT_step14>`

         * :ref:`Reference links <NAT_step15>`

         .. button-link:: ./IPv4_Addressing/NAT.html
            :color: primary
            :shadow:
            :expand:

            Jump to "NAT"

.. tab-set::

  .. tab-item:: Subnetting

      **RFC:** RFC 950

      **Main Features:**

      - Divides larger IP space into smaller, manageable parts.
      - Enhances routing and security.

      **Use Cases:**

      - Enterprise internal segmentation  
      - ISP hierarchical IP design

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

         **Learn More About Subnetting:**

         * :ref:`Learnings in this section <RADIUS_step1>`

         * :ref:`Terminology <RADIUS_step2>`

         * :ref:`Version Info <RADIUS_step3>`

         * :ref:`RADIUS FAQs <RADIUS_step4>`

         * :ref:`RADIUS Version&IEEE Details <RADIUS_step5>`

         * :ref:`RADIUS Basic Setup on Ubuntu using IPv4 <RADIUS_step18>`

         * :ref:`RADIUS Basic Setup on Ubuntu using IPv6 <RADIUS_step19>`

         * :ref:`RADIUS Protocol Packet Details <RADIUS_step6>`

         * :ref:`RADIUS Usecases <RADIUS_step7>`

         * :ref:`RADIUS Basic Features <RADIUS_step8>`

         * :ref:`Reference links <RADIUS_step17>`

         .. button-link:: ./IPv4_Addressing/Subnetting_IPv4.html
            :color: primary
            :shadow:
            :expand:

            Jump to "Subnetting"

.. tab-set::

   .. tab-item:: Unicast

      **RFC:** RFC 791

      **Main Features:**

      - One-to-one data transfer.
      - Most common form of IP communication.

      **Use Cases:**

      - Web browsing  
      - Emails, file sharing

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

         **Learn More About Unicast:**

         * :ref:`Terminology <Unicast_Addressing_step2>`

         * :ref:`Version Info <Unicast_Addressing_step3>`

         * :ref:`Unicast_Addressing FAQs <Unicast_Addressing_step4>`

         * :ref:`Unicast_Addressing Version&IEEE Details <Unicast_Addressing_step5>`

         * :ref:`Unicast_Addressing Basic Setup on Ubuntu using IPv4 <Unicast_Addressing_step18>`

         * :ref:`Unicast_Addressing Basic Setup on Ubuntu using IPv6 <Unicast_Addressing_step19>`

         * :ref:`Unicast_Addressing Protocol Packet Details <Unicast_Addressing_step6>`

         * :ref:`Unicast_Addressing Usecases <Unicast_Addressing_step7>`

         * :ref:`Unicast_Addressing Basic Features <Unicast_Addressing_step8>`

         * :ref:`Reference links <Unicast_Addressing_step17>`

         .. button-link:: ./IPv4_Addressing/Unicast_Addressing.html
            :color: primary
            :shadow:
            :expand:

            Jump to "Unicast"