IPv6's Failure: A 30-Year Retrospective

This article reflects on the 30-year journey of IPv6, from its initial design principles to its current practical applications, delving into the reasons why IPv6 failed to replace IPv4. The author points out that IPv6, in its initial design to simplify the transition, added new features that led to complexity. For example, extension headers are difficult to parse, and the multi-addressing mechanism has increased the difficulty of implementation and deployment. The author argues that there were key mistakes in the IPv6 design, such as the use of 128-bit addresses, inclusion of fragmentation handling and extension headers. Ultimately, these problems led to IPv6 deployment and adoption being far lower than expected, and in some ways inferior to IPv4.