Most switch/router dataplane processing is done in hardware, with control by custom drivers in the control-plane OS. Cisco IOS is variously hosted on a proprie

Most switch/router dataplane processing is done in hardware, with control by custom drivers in the control-plane OS. Cisco IOS is variously hosted on a proprietary real-time OS, QNX or Linux. Juniper JunOS is FreeBSD-based. Arista AOS is Linux-based. With the advent of SDN, the packet-rate limitations of a general-purpose OS lead to things like DPDK and Snabb, but they both run within a Linux host environment (DPDK can use FreeBSD as well; not sure re: Snabb).