Q:

how to implement a network that communicates with the internet without NAT?

nowadays most of the LAN networks use NAT to link all the computers to the internet using only one External IP address. what if have only one computer and i want it to use that external ip address directly on it's interface without using NAT, PAT and PortForwarding as it's nowadays done for global IPV6 adddresses ??? how it can be technically done ??? is there additional devices that should be present to implement this solution or should the router be replaced by another equipment ??? 

A:

IPv4 or IPv6 doesn't matter, except for the availability of addresses.  These are examples using IPv4.
Topology A is what most people do.  Topology B is what Mike Pennington said.  Topology C is what you can do if you get a few addresses from your ISP.

