There was/is a software called IProute which runs in DOS mode (version 6.22 for sure, probably lower too) and you can run it with no hard disk and with 1meg or ram. I think the slowest system you could run it with was 386/25Mhz!
What this all means is that you can have a dirt cheap router if you want.
Oh yeah, software was shareware, but pretty much is now into abandonware. There is Yahoo user group for that software.