My internet service provider gives me the opportunity of having each device in my home network with its own public IP address.
That is because I do not really have a router; I have a bridge. So what I do when I get a new device, is that I configure my ADSL username/password in the new device and it gets a direct connection to the Internet with a public IP address.
Devices like Slingbox when connected behind a router, get a private IP address and the router performs NAT translation of the private IP address into the public IP address. Also, it is necessary to configure some ports forwarding or redirection. When a device has its own public IP address, NAT is not necessary and therefore NAT and port forwarding are not necessary as well.