switch/NAT vs router

[hongman]

i just need to know what the terminology is for routers that seperate network segments. medium/large business router maybe?

Sounds like you are talking about VLAN's. If you want IP Vlan capability, you will need a Layer 3 switch/router.

If you want a different IP Interface for each physical port, you need to create (example) vlan 2 - vlan 4, and assign ("tag") these vlans to 1 port each. I didnt mention vlan 1, as this is the default vlan. Each vlan can have its own IP Interface then, on a seperate subnet - i.e:

Port 1, VLAN 1, IP Interface 192.168.1.1/24
Port 2, VLAN 2, IP Interface 192.168.2.1/24
Port 3, VLAN 3, IP Interface 192.168.3.1/24

etc.

Hope this helps?