What does “BCP” really mean?

In this episode of PING, APNIC Chief Scientist Geoff Huston discusses an emerging concern about how the IETF interprets the concept of ‘Best Current Practice‘ (BCP). In his previous episode, Geoff explored emerging questions around DNS provisioning over IPv6, including experimental observations on its performance characteristics. Towards the end of the discussion, we turned to how the Internet Engineering Task Force documents standards and protocols through Best Current Practice (BCP) publications. In the traditional view, BCPs are intended to provide clear, implementation-focused guidance that remains neutral across different operational contexts. This includes networks of all scales — from home environments to enterprise, national, and international infrastructure. These systems rely on a shared understanding of protocol behaviour, and BCPs help define the set of practical, interoperable choices available for deployment today. To be designated as a BCP, an IETF RFC undergoes additional review and scrutiny. This is similar to the ‘Standard’ (STD) designation, which elevates an RFC beyond a general publication and gives it greater weight in operational and procurement contexts. While RFCs are not legally binding, they are frequently referenced in national regulations, procurement frameworks, and service specifications. In contrast, Experimental and Informational RFCs explicitly indicate that they are not intended for such use. BCPs, along with Proposed Standards and Standards, carry greater normative weight due to the more rigorous processes required for their approval, making them more suitable as references for real-world deployment and decision-making. An emerging perspective suggests that BCPs may be treated as aspirational as well as definitional — potentially describing behaviours that are not yet widely deployed, or in some cases not deployed at all. This represents a subtle shift from the traditional view of BCPs as documenting established, operational practice. This tension has surfaced in discussions around the DNS/IPv6 draft mentioned in the earlier PING episode. The conversation involves multiple parts of the IETF process, including the DNSOP Working Group, the DNS Directorate (which reviews DNS-related work across Working Groups) and the Internet Engineering Steering Group (IESG), responsible for final document review and status approval before publication as an RFC. These discussions reflect an evolving question: Should BCPs remain a record of established operational consensus, or can they also serve to guide and shape future practice? Advocacy is an important part of the IETF process. But it’s important to distinguish between advocating for a new path in systems and specifying what the current best choice is in the specification of systems behaviour.