Network protocols are formal standards and policies comprised of rules, procedures and formats that define communication between two or more devices over a network. Network protocols govern the end-to-end processes of timely, secure and managed data or network communication.
Techopedia explains Network Protocols
Network protocols incorporate all the processes, requirements and constraints of initiating and accomplishing communication between computers, servers, routers and other network enabled devices. Network protocols must be confirmed and installed by the sender and receiver to ensure network/data communication and apply to software and hardware nodes that communicate on a network.
There are several broad types of networking protocols, including:
Network communication protocols: Basic data communication protocols, such as TCP/IP and HTTP
Network security protocols: Implement security over network communications and include HTTPS, SSL and SFTP.
Network management protocols: Provide network governance and maintenance and include SNMP and ICMP.