This Recommendation describes the extended functions for B-PON systems defined in ITU-T Rec. G.983.1 to enable protection functions. It is based on Appendix IV/G.983.1. In particular@ it focuses on the protection-configuration types B and C described in that appendix. This Recommendation discusses a number of protection feature and function choices and provides the necessary specifications in the PON layer to implement these choices. These include guidelines on performance objectives (for example@ switching and detection time)@ application functionality (for example@ revertive mode@ non-revertive mode@ extra traffic support@ automatic switching@ and forced switching)@ switching criteria and switching protocols (1+1@ 1:1@ 1:N@ bidirectional and unidirectional mechanisms). This Recommendation considers protection enhancements for the delivery of highly reliable services for a variety of B-PON network scenarios@ including Fibre to the Cabinet (FTTCab) and Fibre to the Office (FTTO).