Tim's Technology Journey Wiki

Dual-Stack Network

IPv4 and IPv6 operate at the same time over a common or disparate link/s.
Considered a transition technology because it is not meant to be in operation forever. It is meant as a band-aid while IPv4 is depreciated from the network.
All devices must support IPv6, otherwise, dual-stack will not work.
Software and hardware upgrades may be required as well a network redesign (partial or full) in order to deploy IPv6 everywhere.

Tunneling

Can either encapsulate IPv4 packets within IPv6 or IPv6 packets within IPv4 in order to provide connectivity.
RFC 6144
Dual-stack hosts are needed or interoperability.
Users of the new architecture cannot use the services of the underlying infrastructure.

Translation

aka AFT (Address Family Translation)
Manages communication between IPv6-only and IPv4-only hosts and networks using IP header and address translation between the two address families.
Provides a gradual migration to IPv6.
Provides business continuity to IPv4 users.
ALG (Application-layer Gateway) provides support for translation to specific protocols, such as FTP and SIP which embed IP address information within the payload.

NAT64

AFT using NAT64 technology can be achieved by either stateless or stateful means

Stateless (RFC 6145) NAT64 is a translation mechanism for algorithmically mapping IPv6 addresses to IPv4 addresses and vice-versa. Doesn't maintain any bindings or session state while performing translation for either IPv4 or IPv6 initiated communications.
Stateful (RFC 6146) NAT64 transition IPv6 addresses to IPv4 addresses, and vice-versa. NAT64 creates or modifies bindings or session state while performing translation. Uses static or manual bindings
Comparison between stateless and stateful NAT64

Stateless NAT64	Stateful NAT64
1:1 translation, hence applicable for a limited number of endpoints	1:N translation, hence no constraint on the number of end points therefore, also applicable for carrier grade NAT (CGN)
No conservation of IPv4 address	Conserves IPv4 address
Helps ensure end-to-end address transparency and scalability	Uses address overloading; hence lacks end-to-end address transparency
No state or bindings created on the translation	State or bindings created on every unique translation
Requires IPv4-translatable IPv4 address assignment (mandatory requirement)	No requirement for the characteristics of IPv6 address assignment
Requires either manual or DHCPv6-based address assignment for IPv6 hosts	Capability to choose any mode of IPv6 address assignment: manual, DHCPv6, or stateless address autoconfiguration (SLAAC)

* NAT64 is preferred choice for AFT