OSI model and TCP/IP networking fundamentals
Dynamic routing concepts (e.g., OSPF, BGP, EIGRP or similar)
IP addressing and subnetting
Common network topologies (e.g., star, mesh, hub-and-spoke)
Network and physical security principles
Authentication and authorization concepts (e.g., RADIUS, TACACS+, 802.1X)
Encryption fundamentals and secure protocols
Firewalls, VPN technologies (remote access and site-to-site), and wireless security
Ability to use network analysis tools (e.g., packet captures, traceroute, ping, SNMP-based tools, log analysis) for diagnostics.
Ability to follow and improve standard operating procedures and technical documentation.