- IPv4 Address: Comprising 32 bits, an IPv4 address is split into four sections called octets, each containing 8 bits. This addressing scheme allows devices to be uniquely identified on a network.
- Subnet Mask: The subnet mask helps determine the division between the network and host portions of an IPv4 address. It consists of ones followed by zeros. The ones represent the network, while the zeros denote the host.
- Classless IPv4 Addressing: In classless addressing, there’s no fixed class structure like A, B, or C. This allows for more flexible allocation of IP addresses based on network requirements.
- Classful: Classful addressing follows a predefined class structure (A, B, C, etc.) and includes an implicit subnet mask. It’s less flexible than classless addressing.
- CIDR: Classless Inter-Domain Routing (CIDR) is an improved IP addressing system that eliminates the rigidity of classful addressing. It optimizes address allocation and reduces address wastage.
- Illustrative Subnet Mask: The subnet mask 255.255.255.252 is equivalent to CIDR /30. The binary representation 11111111 11111111 11111111 11111100 translates to /30.
- Migration to Classless Addressing: Classless addressing overcomes limitations of fixed class sizes in classful addressing, allowing better utilization of address space.
- CIDR Notation: CIDR notation combines the IP address and prefix length (e.g., 192.168.20.2/24). The prefix length defines the network portion.
- IANA: The Internet Assigned Numbers Authority allocates IP addresses globally to ensure uniqueness and proper network functioning.
- RIRs: Regional Internet Registries receive IP address allocations from IANA and distribute them to ISPs based on geographical regions.
- ICANN: The Internet Corporation for Assigned Names and Numbers oversees IP address management and DNS root zone registries in line with IANA’s guidance.
- Private IP Addresses: Private IP address ranges (e.g., 192.168.x.x) are reserved for internal use within networks and aren’t routable on the public internet.
- DHCP: Dynamic Host Configuration Protocol assigns IP addresses to devices dynamically, reducing the need for manual configuration.
- DHCP Servers: Servers responsible for managing and distributing IP addresses through DHCP, streamlining network setup.
IPv6 Addressing:
- IPv6: Uses unicast for one-to-one communication, multicast for one-to-many within specific groups, and anycast to transmit to the nearest device in a group.
- IPv6 Address Space: IPv6 provides an enormous number of unique addresses (340 Trillion Trillion Trillion), addressing the limitations of IPv4’s address exhaustion.
- Anycast: Anycast is employed in DNS and content delivery networks (CDNs) to direct users to the closest server for improved performance.
- Multicast: Multicast sends data to devices in a specific group, making it efficient for tasks like streaming to multiple recipients.
- IPv6 Multicast: IPv6 multicast addresses use the ff00::/8 prefix to identify multicast group addresses.
- Unspecified Addresses: In IPv6, an unspecified address is represented by eight zeros (::/128), equivalent to the IPv4 loopback (127.0.0.1).
- Link-Local IPv6 Address: Similar to IPv4’s loopback, a link-local IPv6 address (e.g., 0:0:0:0:0:0:0:1 or ::1/128) allows a device to communicate with itself.
- Global Unicast Address: Comparable to IPv4’s public IP, a global unicast IPv6 address is globally routable, allowing direct communication across the internet.
- Unicast: Unicast is a one-to-one connection mechanism used in various protocols like HTTP, SMTP, IMAP, FTP, and DNS. It ensures data reaches a specific recipient.