Overview#RFC Sub-series is a classification of the Request For Comment publications
RFC Sub-series contains three sub-series:
- BCP - Best Current Practice; mandatory IETF RFCs not on standards track, see below.
- FYI - (OBSOLETE) For Your Information; informational RFCs promoted by the IETF as specified in RFC 1150 (FYI 1). In 2011, RFC 6360 obsoleted FYI 1 and concluded this RFC Sub-series.
- STD - Internet Standard; this used to be the third and highest maturity level of the IETF standards track specified in RFC 2026 (BCP 9). In 2011 RFC 6410 (a new part of BCP 9) reduced the standards track to two maturity levels.