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IP address

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An Internet Protocol address, or IP address, is a numerical label assigned to every device on a computer network. These labels are essential for digital communication using the Internet Protocol. An IP address serves two primary functions. First, it provides network interface identification to distinguish one device from another. Second, it provides location addressing. This location data allows the network to establish a specific path to a host. One way to think about this is through three distinct roles: a name indicates what is being sought, an address indicates where it is located, and a route indicates how to get there.

IPv4 address structure and writing systems-en
IPv4 address structure and writing systems-en

To understand how these addresses function, one must look at the structure of the data packets. Each IP packet contains a header. This header includes the IP address of the sending host and the IP address of the destination host. This allows routers to move information across the network to the correct location. Addresses can be assigned in different ways. A network administrator might use a static assignment, which is fixed or permanent. Alternatively, they might use a dynamic assignment, where the address changes based on software features or network practices.

There are two main versions of the Internet Protocol in common use today. The first is Internet Protocol version 4, or IPv4. This version was first deployed in 1983 within ARPANET, the predecessor to the modern Internet. IPv4 addresses are 32-bit numbers. This means they are composed of 32 binary digits. Humans usually see these as dot-decimal notation. This notation uses four decimal numbers separated by dots, such as 192.168.1.1. Each of these four numbers is an octet, representing 8 bits, and ranges from 0 to 255.

Ipv6 address
Ipv6 address

Because IPv4 uses only 32 bits, the total number of available addresses is limited to approximately 4.3 billion. As the Internet grew rapidly during the 1990s, this address space began to run out. This led to IPv4 address exhaustion throughout the 2010s. To solve this, the Internet Engineering Task Force developed Internet Protocol version 6, or IPv6, in 1995. IPv6 uses 128 bits for its addresses. This provides a massive address space of approximately 340 undecillion addresses. While IPv6 deployment began in the mid-2000s, IPv4 and IPv6 are still used side-by-side today.

Managing these addresses requires a global hierarchy. The Internet Assigned Numbers Authority, or IANA, manages the IP address space globally. IANA assigns large blocks of addresses to five regional Internet registries, known as RIRs. These RIRs are responsible for distributing those blocks to local Internet registries. These local registries include large institutions and Internet service providers, or ISPs. Some addresses are reserved for private networks and are not globally unique. For example, a factory might use private addresses for machines that only communicate with each other. These private addresses are not routed on the public Internet.

Networks are often divided into smaller sections called subnetworks. This process is known as subnetting. An IP address can be divided into a network prefix and a host identifier. The network prefix identifies the specific network, while the host identifier numbers the devices within that network. In IPv4, a subnet mask is used to define this division. In both IPv4 and IPv6, experts use Classless Inter-Domain Routing, or CIDR, notation. CIDR uses a slash followed by a number to show how many bits belong to the routing prefix. For instance, 192.168.1.0/24 means the first 24 bits are the prefix. This is a more flexible method than the older, obsolete classful network architecture.

IPv4 address structure and writing systems-en
IPv4 address structure and writing systems-en
Ipv6 address
Ipv6 address

History shows that addressing methods have changed to meet new needs. In the early days, the network number was always the highest-order octet. This limited the system to only 256 networks. In 1981, the classful network architecture was introduced to allow more assignments. This system used Classes A, B, and C based on the leading bits of the address. However, this system lacked scalability for the rapid expansion of the 1990s. Consequently, the classful system was replaced by CIDR in 1993. Today, the large capacity of IPv6 allows for more efficient routing and better management of network segments. This ensures the Internet can continue to grow for the foreseeable future.

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