Proteon was shipping NAT (NAPT) in routers in 1994 or there abouts, well before Cisco. It was popular on the small GT60 router, especially in southeast asia, where ISPs wouldn't give out anything other than single addresses, and at the time getting a dedicated link was nearly impossible. NAT (NAPT) allowed them to connect up small offices.
Of course Proteon neglected to tell the world about this or most other features. Marketing really does matter...