This is the first tutorial in the IP address series. It is followed by How the Internet Forwards Packets, Network Address, Classful, and Subnetting.

Q1. Why is the IP address required?

Answer: The phones are connected to the telephone network to exchange voice messages. A unique phone number is assigned to each phone.

The Internet is similar to the telephone network. IP stands for Internet Protocol. It defines a set of rules for exchanging digital messages on the Internet. Computers are connected to the Internet to transfer messages in smaller packets. Each computer is assigned a unique IP address. Each packet is labeled by a source address and a destination address. The Internet uses the destination address to forward packets to their destination. The source address is used by the destination to reply.

Q2. What is the structure of the IP address?

Answer: Contains 32 bits or 4 bytes (8 bits/byte). It is usually presented as 4 decimal numbers like abcd. Each decimal is assigned to a byte. The range of each decimal is 0~255.

For example, Jack’s address can be presented in two ways:

– Number four decimal places 100.4.5.6, gold

– A 32-bit binary number 01100100.00000100.00000101.00000110

Q3. How many IP addresses are there?

Answer: Around 4.2 trillion (2^32=4,294,967,296). Seems like a lot. but is not. Internet addresses are scarce. The 32-bit address was devised in the early 1980s and called IPv4. The newer one is called IPv6 with a 128-bit address.

Q4. What is the Internet?

Answer: A simplified definition is that the Internet is a collection of routers that connect computers and provide communication services between computers. Use Google to search “internet”, you will find many good tutorials.

Q5. How does the Internet deliver computer messages?

Answer: The Internet is made up of many routers. The router’s job is to forward packets according to the receiver’s address included in the packet’s network headers.