Recently, people feel evil accessing to the Internet when they use NAT/NAPT in many cases. The reason of this situation might increases many interactive communication softwares using high bandwidth and permanent connection such as xDSL. Especially, some internet telephone softwares and some internet games connect from their server or a person on the other end of telephone call to residential terminals which is placed behind NAT/NAPT directly. In this case, NAT/NAPT boxes can not decide to forward their connection to residential terminal. That is when people uses those software they saliently feel evil of NAT/NAPT.
The best solution for improving this evil is IPv6. Because IPv6 has many number of addresses, and IPv6 address might be assigned all of end-host including residential network. IPv6 solutions already work, and some ISPs already provide services using IPv6. However, most of these are trials even now.
In this situation, recent application softwares become more intelligent, and many useful applications have appeared. However, NOW, most people can not use those useful applications because they use NAT/NAPT for connecting network. It is very unfortunate situations.
"NATS" is the only one which will definitely improve CURRENT problems. In some times, NATS invites misunderstanding what NATS prevents to encourage IPv6. In fact, many networks use NAT/NAPT, and IPv4 address consumption have progressed. However, IPv4 address consumption did not stop. That is, NAT/NAPT can not avoid to consume IPv4 addresses. It is no doubt that many terminals need more IP addresses than now if people do not use NAT/NAPT. However, current internet situation shows that most people need NAT/NAPT for connecting to the Internet. When we consider those situation, we must improve "CURRENT PROBLEMS" to use "NATS".