said by bimmerdriver: Port forwarding is not the same thing as NAT.
They are not the same thing, however one is related to the other.
Port forwarding involves NAT. NAT doesn't neccessarily involve port forwarding. (port forwarding is also called DNAT, destination nat. You are NAT'ing the destination of the IP packet.) Any DMZ I've seen simply Port Forwards (involving NAT) ALL ports to the (first routers) 'internal' IP. This internal IP then goes to the WAN interface of another router, and get's NAT'd (and possibly port forwarded) again.
Regular NAT is technically SNAT (source nat). The router takes traffic from multiple source IP's (internal lan ips), and changes the source IP to be it's own public IP. Sends the packet out, and waits for replies. When replies come back in, it figures out which packet goes to which internal ip (usually via hash lookup tables), and rewrites the IP header so that the whole NAT process is (fairly) transparant.
Telus sure needs a more flexible TV solution, or they should be giving technical users the knowlege on how their tv system works, so advanced users can duplicate it with their existing hardware.