The most widely used and available protocol is TCP/IP i.e. Transmission Control Protocol and Internet Protocol. TCP/IP specifies how data should be packaged, transmitted and routed in their end to end data communication.
There are four layers as shown in the below diagram:
Given below is a brief explanation of each layer:
Application Layer: This is the top layer in the TCP/IP model. It includes processes that use the Transport Layer Protocol to transmit the data to their destination. There are different Application Layer Protocols such as HTTP, FTP, SMTP, SNMP protocols, etc.
Transport Layer: It receives the data from the Application Layer which is above the Transport Layer. It acts as a backbone between the host’s system connected with each other and it mainly concerns about the transmission of data. TCP and UDP are mainly used as Transport Layer protocols.
Network or Internet Layer: This layer sends the packets across the network. Packets mainly contain source & destination IP addresses and actual data to be transmitted.
Network Interface Layer: It is the lowest layer of the TCP/IP model. It transfers the packets between different hosts. It includes encapsulation of IP packets into frames, mapping IP addresses to physical hardware devices, etc.