What is TCP/IP?

The Internet Protocol Suite (commonly known as TCP/IP) is the set of communications protocols used for the Internet and other similar networks. 
It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard.
 The TCP/IP model consists of four layers. From lowest to highest, these are the: 

• Link Layer (2) 
• Internet Layer (3) 
• Transport Layer (4) 
• Application Layer (7)