What do both Carrier Grade NAT and NAT64 have in common?

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_nat/configuration/xe-3s/asr1000/nat-xe-3s-asr1k-book/iadnat-cgn.html
Carrier Grade Network Address Translation (CGN) is a large-scale NAT that translates private IPv4 addresses into public IPv4 addresses. CGN employs Network Address and Port Translation methods to aggregate multiple private IPv4 addresses into fewer public IPv4 addresses.

Network Address Translation (NAT) is positioned between a private and public IP network and uses nonglobal, private IP addresses and a public IP address for translation. NAT dynamically maps one or more private IP addresses into one or more public (globally routable) IP addresses that use Network Address and Port Translation (NAPT) techniques.

Connecting IPv6 and IPv4 Networks
http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/enterprise-ipv6-solution/white_paper_c11-676278.html
Three main options are available for migration to IPv6 from the existing network infrastructure: dual-stack network, tunneling, and translation.

To provide a seamless Internet experience to users accessing IPv4 Internet services through completely new (“greenfield”) IPv6-only networks. Established content providers and content enablers can transparently provide existing or new services to IPv6 Internet users by deploying Network Address Translation IPv6 to IPv4 (NAT64) technology.

Network Address Translation IPv6 to IPv4, or NAT64, technology facilitates communication between IPv6-only and IPv4-only hosts and networks (whether in a transit, an access, or an edge network). This solution allows both enterprises and ISPs to accelerate IPv6 adoption while simultaneously handling IPv4 address depletion.