IPv6-to-IPv6 Network Prefix Translation (NPTv6) performs a stateless, static translation of one IPv6 prefix to another IPv6 prefix (port numbers are not changed). There are four primary benefits of NPTv6:
You can prevent the asymmetrical routing problems that result from Provider Independent addresses being advertised from multiple datacenters. NPTv6 allows more specific routes to be advertised so that return traffic arrives at the same firewall that transmitted the traffic. Private and public addresses are independent; you can change one without affecting the other. You have the ability to translate Unique Local Addresses to globally routable addresses.
This topic builds on a basic understanding of NAT. You should be sure you are familiar with NAT concepts before configuring NPTv6.

Related Documentation