An Internet Protocol (IP) address is a numerical identification and logical address that is assigned to devices participating in a computer network utilizing the Internet Protocol for communication between its nodes.

The original designers defined an IP address as a 32-bit number, now named as Internet Protocol Version 4 (IPv4), and are still in use today. However, due to the enormous growth of the Internet and the resulting depletion of the address space, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995 and last standardized by RFC 2460 in 1998.

Although IP addresses are stored as binary numbers, they are usually displayed in human-readable notations, for e.g., 208.77.188.166 (for IPv4) and 2001:db8:0:1234:0:567:1:1 (for IPv6). The role of the IP address has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there." IP addresses are considered software addresses, and are not hard coded hardware addresses.

The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally. IANA works in cooperation with five Regional Internet Registries (RIRs) to allocate IP address blocks to Local Internet Registries (Internet service providers) and other entities.

IP addresses are categorized into two categories:
•    Private Addresses: These are addresses that are used on the private network, and which are not visible on the Internet. They are often used with network address translators to connect to the global public Internet.
•    Public Addresses: These are Internet Assigned Numbers Authority (IANA) registered addresses which are visible on the Internet.

IP version 6 addresses
The next generation of the Internet Protocol, aimed to replace IPv4 and to expand the Internet's addressing capability on the Internet, was eventually named Internet Protocol Version 6 (IPv6). The address size was increased from 32 to 128 bits or 16 octets, which, even with a generous assignment of network blocks, is deemed sufficient for the foreseeable future.

Static and dynamic IP addresses
When a computer is configured to use the same IP address each time it powers up, this is known as a Static IP address. In contrast, in situations when the computer's IP address is assigned automatically, it is known as a Dynamic IP address.

IP Address Assignment Methods
IP addressing can occur through either of the following methods:
•    Dynamically assigning IP addresses through Dynamic Host Configuration Protocol (DHCP): IP addresses that are assigned via a DHCP server are regarded as dynamically assigned IP addresses. The DHCP server assigns IP addresses from a predetermined IP address range(s).
•    Manually assigning IP addresses: Manually assigning IP addresses can be time consuming, and can lead to duplicated IP address assignments. IP addressing normally occurs manually when there are no configured DHCP servers on the network and the network haves multiple network segments or a computer has a static IP addresses or the user configure computers on important network servers such as domain controllers, or DNS servers.
•    Automatically assigning IP addresses through Automatic Private IP Addressing (APIPA): APIPA can be used as an alternative when no DHCP server exits to dynamically assign IP address. APIPA works well in smaller networks, when a computer is used on more than one network.

Special IP addresses:
A few IP addresses are reserved for specific special purposes. The reserved IP addresses are:
•    Network segment of the address specified to zeros/0s: Indicates this network or subnet (local network).
•    Network segment of the address specified to ones/1s: Indicates this network and all associated subnets.
•    Network address 127: The address is reserved for loopback testing.
•    Host address of all zeros/0s: The address is typically used in routing tables, and when referencing a network, but not particular hosts on the network.
•    Host address of all ones/1s: This is used as a broadcast address for all the nodes on a particular network.

Renu Singh/ITvoir Network