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**Here is the link to the fantastic Cisco FAQ that details the use cases for when you would want to use NVI vs. domain NAT***
http://www.cisco.com/c/en/us/support/docs/ip/network-address-translation-nat/26704-nat-faq-00.html
In this video tutorial we take a look at Cisco Networking Academy Lab 6-1 on Network Address Translation (NAT). We compare and contrast classic/domain NAT with NAT Virtual Interface (NVI) and see how static and dynamic NAT work. Enjoy!