Protocol VLAN environment
The figure in Multiple port-based VLANs illustrates a protocol VLAN environment also. In this case, VLANs W and X represent routable protocol VLANs. VLANs Y and Z can be any protocol VLAN.
As noted for the discussion of multiple port-based VLANs, VLAN 1 is not shown. Enabling internal (IP) routing on the switch allows IP traffic to move between VLANs on the switch, but routable, non-IP traffic always requires an external router.