IP address
An IP address is used to uniquely address a computer in a computer network. This allows a computer to be identified and reached on the network. An address can be assigned to several computers (as long as they do not want to establish an Internet connection at the same time). It is also possible for a computer to be linked to several IP addresses. The IP address is particularly relevant with regard to data transmission on the Internet. Routers that are part of the Internet or an internal network receive sent data packets. These contain information in the header about the address to which the data packet is to be sent. The router can then forward the information to the destination computer or to the next router in the network.
Structure of an IP address
There are basically two types of IP addresses. The standard in use today is called “IPv4”. In this case, an IP address consists of 32 bits or four octets, i.e. four integers that can range from 0 to 255. They are separated by three dots, for example 192.0.2.0. This results in 2^32, or around 4.3 billion possible IP addresses that can be assigned to computers. In practice, there are considerably fewer, since some ranges are reserved for special purposes. The IPv4 standard will gradually be replaced by the IPv6 standard in the future, as it is too limited in the long term for the expansion of the World Wide Web. IPv6 comprises 128 bits and thus offers 3.4 x 10^38 possible IP addresses. Since the resulting addresses would be confusing, an IP address according to this standard consists of eight four-digit combinations of numbers and letters separated by a colon. The basic scheme looks like this: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx. This is a hexadecimal representation where two octets of the IP address are combined.
Assignment of IP addresses
IP addresses are assigned by the “Internet Assigned Numbers Authority” (IANA) in cooperation with regional assignment offices. In the past, they did not assign a single IP address, but distributed the numbers directly to companies in blocks of several million addresses, thanks to the supposed abundance. Today, IANA allocates IP addresses in blocks to five regional allocation bodies, the “Regional Internet Registries” (RIR), which are responsible for the regions/continents of Africa, Asia-Pacific, North America, Latin America/Caribbean, and Europe/Middle East/Central Asia. Local registries, also known as “Local Internet Registries” (LIR), are assigned addresses by the RIRs and can allocate a single IP address or entire blocks to their customers. Internet service providers often act as LIRs. In private networks, companies can use IP addresses from specific address ranges reserved for this purpose.
