[musicale]

> Linux seems like it would be a bit heavy for a switch

Linux (and other Unix or Unix-like) kernels (and indeed full OS distributions) run fine on many low-end and embedded CPUs and hardware, and network switches are no exception.

OpenWRT is Linux-based and runs on extremely low-end switches such as home routers and access points.

Arista EOS is based on Fedora. (Of course Arista switches have real server CPUs and lots of memory. People do crazy things like running KVM on them.)

Juniper's Junos is based on BSD.

Remember that on a high-speed switch packets usually pass through the switching hardware without touching the switch CPU. Programmable switching chips like Tofino typically run pre-compiled pipelines that execute on-chip at line rate. The switch OS is primarily used for running management software that programs the hardware, runs the CLI, and/or provides other services. The OS can also run software to provide higher-level protocols and services such as BGP, DNS, or DHCP.