internet | Protocol of the Internet

Every machine on the Internet has a unique identifying number, called an IP Address. The IP stands for Internet Protocol, which is the language, that computers use to communicate over the Internet. A protocol is the pre-defined way that someone who wants to use a service talks with that service. The "someone" could be a person, but more often, it is a computer program like a Web browser.
A typical IP address looks like this:
151.8.151.16

To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a dotted decimal number like the one above. But computers communicate in binary form. Look at the same IP address in binary:
10010111.00001000.10010111.00010000
The four numbers in an IP address are called octets, because they each have eight positions when viewed in binary form.

• If you add all the positions together, you get 32, which is why IP addresses are considered 32-bit numbers.
• Since each of the eight positions can have two different states (1 or zero), the total number of possible combinations per octet is 28 or 256.
• Therefore, each octet can contain any value between zero and 255.
• Combine the four octets and you get 232 or a possible 4,294,967,296 unique values!
  Out of the almost 4.3 billion possible combinations, certain values are restricted from use as typical IP addresses.
• For example, the IP address 0.0.0.0 is reserved for the default network and the address 255.255.255.255 is used for broadcasts.
• The octets serve a purpose other than simply separating the numbers. They are used to create classes of IP addresses that can be assigned to a particular business; government or other entity based on size and need.
• The octets are split into two sections: Net and Host.
• The Net section always contains the first octet. It is used to identify the network that a computer belongs to.
• Host (sometimes referred to as Node) identifies the actual computer on the network. The Host section always contains the last octet.
• There are five IP classes plus certain special addresses.