Common network protocols
TCP/IP: the foundation of the Internet. HTTP/HTTPS: web communication. DNS: name resolution. DHCP: dynamic IP allocation. SNMP: network management. NetFlow/sFlow: traffic monitoring.
Protocol layer structure
Network protocols are commonly divided into the OSI seven-layer model or the TCP/IP four-layer model. Understanding the layers helps with troubleshooting: physical layer affects electrical signals, data link affects MAC, network affects IP routing, transport affects TCP/UDP, application affects service communication.