An IP address is a unique address for network equipment. It is designed to identify personal computers, hubs, switches or routers within the network.
An IP address has two parts. The first part is the network number, which can be chosen by the administrator arbitrarily, or in accordance with the recommendation of a special Internet unit (Network Information Center, NIC). The second part of the IP address is the host number, which is set regardless of the host address. The entire address is a four-byte message of the form 192.168.1.200. Each number in this group is the value of one of the bytes, written in decimal form. We can say that an IP address does not characterize a single computer or hub, but one connection of a given local or global network.
All IP addresses can be divided into several classes. Class A Networks of this type have numbers in the range from 1 to 126, and number 127 is reserved for feedback when testing the operation of the host software without actually sending a packet over the network. This address is called loopback. The network address number occupies one byte, the other three are for host and network numbers.
Class B The range of numbers for such networks is 128-191. 2 bytes are allocated for the address part of the network and the node. Class SS Networks of this class are intended for use no more than 28 nodes. The addressing range is in the range of numbers 192-223. The address part is 3 bytes, and the host address is one.
Class D This class denotes a special, multicast address, the address of which is not divided into the fields of the network and host numbers. In this case, the nodes automatically identify which group they belong to. Packets of information sent over the network are received by all nodes of this type at once. The range of numbers is 224-239.
Class E This type is not currently used, it is reserved for future use. For details on the IP address classes, see the figure.