Protocols are rules and protocol stacks are a set of rules that work together to accomplish a common goal. Network protocols are rules about sending, receiving, and packaging data. TCP/IP is the network protocol stack used by the Internet and it has four layers- Application, Transport, IP, and Network. The network layer is also sometimes called the hardware or link layer.
The application layer contains application-specific protocols and is the layer closest to the user. The transport protocol is the TCP layer. It creates network packets and is in charge of quality assurance. The IP layer is responsible for addressing and routing network packets. Lastly, the network layer converts the binary packet data to network signals and sends them out through the network.