Migration from IPv4 to IPv6 (1)

Due to the design defect of the IPv6 protocol, it cannot be compatible with IPv4, which makes the current phase unable to achieve overall migration to the IPv6 network. It is reported that IANA, The Global IPv4 Address Allocation Management Organization, released the last remaining IPv4 address at the beginning of this year. That is to say, the global IPv4 address has been allocated, so IPv6 is urgently needed.

IPv6 Migration Technology

Due to the size of the Internet and the large number of IPv4 users and devices in the current network, the transition from IPv4 to v6 cannot be achieved at one time. Moreover, the daily work of many enterprises and users is increasingly dependent on the Internet, and they cannot tolerate problems arising during protocol transition. Therefore, the industry agrees that IPv4 and IPv6 networks will coexist for a long time. While experiencing the benefits of IPv6, it can still communicate with other IPv4 users in the network. The smooth transition from IPv4 to IPv6 is also an important factor for the success of IPv6.

In fact, IPv6 has taken into account the transition from IPv4 to IPv6 in the design process, and provides some features to simplify the transition process. For example, an IPv6 address can use an IPv4-compatible address, which is automatically generated by an IPv4 address. You can also build a tunnel on an IPv4 network to connect to an IPv6 Island. At present, many mechanisms have been put forward for the IPv4-v6 transition problem, their implementation principle and application environment have their own emphasis, this part will give a systematic introduction to the basic strategy and mechanism of IPv4-v6 transition.

In the transition from IPv4 to IPv6, the following principles and objectives must be followed:

◆ Ensure intercommunication between IPv4 and IPv6 hosts;

◆ Avoid dependency between devices during the update process, that is, update of a device does not depend on updates of other devices );

◆ For network managers and end users, the transition process is easy to understand and implement;

◆ Transition can be performed one by one;

◆ Users and operators can decide when and how to transition.

The transition from IPv4 to IPv6 mainly consists of three aspects: IP layer transition policies and technologies, Link Layer Support for IPv6, and IPv6 impact on the upper layer.