Layer-3 technologies: IPv4 and IPv6, Routing protocols such as static routing, RIP, OSPFv2/3 and BGP, MPLS, Multicast – IGMPv2/3, PIM-SM, PIM-DM, MLDv1/2 etc.
Application protocols like DHCP, TFTP, Telnet, SNTP, Timep SNMP etc.
Network Security: 802.1x, Radius, TACACS, Web-Auth, Mac-Auth, SSH/SSL, IPsec/MacSec etc.
Good understanding of Real Time Operating System (RTOS) like Linux, Green Hills, VxWorks etc. is preferred
Knowledge of ASIC architectures (like Broadcom based) is a plus