This document discusses the requirement for all IP-capable nodes to support IPv6 given the depletion of IPv4 address space. It advises that IPv6 support is no longer optional, and cautions that references to "IP" may refer to IPv4, IPv6, or both depending on context. The document then provides an overview of IPv6 fundamentals including addressing, interconnectivity, security, staff training, and transition approaches. It emphasizes that IPv6 works in practice and addresses challenges but nothing that can't be overcome.