NAT 46 and NAT 64
NAT 46 technology is used when you want to connect an IPv4 to IPv6.
NAT 64 technology is used when you want to connect an IPv6 to IPv4.
Communication Between IPv4 and IPv6
Since IPv6 is not backward compatible with IPv4, we need transition mechanisms to allow communication between them. These mechanisms fall into three main classes:
1. Dual-Stacked Interfaces
Description: Dual-stack interfaces allow devices to communicate using both IPv4 and IPv6. This solution is the simplest for IPv4 and IPv6 co-existence (not interoperability). The interface can speak IPv4 to IPv4 devices and IPv6 to IPv6 devices.
How it works: The version used depends on either the version of the packets received from the device or the type of address returned by DNS when querying for a device address.
Challenge: Dual stacking was initially intended to transition from IPv4 to IPv6 before IPv4 address depletion. However, since IPv4 addresses are still in use and not enough IPv4 addresses are available, dual stacking becomes more complex. The challenge is assigning both an IPv4 and IPv6 address to every interface when there are not enough IPv4 addresses available.
2. Tunnels
Description: Tunnels are used for co-existence, not interoperability. They allow devices or sites of one version (IPv4 or IPv6) to communicate across a network segment or the Internet using the other version.
How it works: For example, IPv4 packets can travel across an IPv6 network, and IPv6 packets can travel across an IPv4 network. Tunneling encapsulates packets of one protocol (IPv4 or IPv6) within the other protocol for transmission.
3. Translators
Description: Translators enable interoperability by translating the headers of packets from one protocol (IPv4 or IPv6) to the header of the other version.
How it works: Translation allows direct communication between an IPv4 device and an IPv6 device by converting packets from one version to the other.
Advantages of Translation Over Tunneling:
Seamless Migration: Translation provides a gradual, seamless migration to IPv6, ensuring compatibility during the transition period.
Content Provider Transparency: Translators allow content providers to offer services transparently to IPv6 users, even if the backend infrastructure is IPv4.
Key Considerations:
Translation as a Temporary Solution: Like other transition methods, translation is not a long-term strategy. The ultimate goal should be the native adoption of IPv6. However, translation provides a practical means of facilitating the transition in the short term.