Description: An object that defines the mode of operation of the optional FEC sublayer of the 1000BASE-PX PHY, specified in [802.3ah] clause 65.2, and reflects its state. A GET operation returns the current mode of operation of the PHY. A SET operation changes the mode of operation of the PHY to the indicated value. unknown(1) value is assigned in initialization, for non FEC support state or type not yet known. disabled(2) value is assigned when the FEC sublayer is operating in disabled mode. enabled(3) value is assigned when the FEC sublayer is operating in FEC mode. The write operation is not restricted in this document and can be done at any time. Changing dot3EponFecMode state can lead to disabling the Forward error correction on the respective interface which can lead to a degradation of the optical link and therefore may lead to an interruption of service of the users connected to the respective EPON interface. This object is applicable for an OLT and an ONU. At the OLT it has a distinct value for each virtual interface. The counting of the FEC counters will stop when the FEC of the interface is disabled. The counters: dot3EponFecPCSCodingViolation - not affected by FEC mode. dot3EponFecCorrectedBlocks - stops counting when Rx_FEC is not enabled. (unknown (1) and disabled (2)). dot3EponFecUncorrectableBlocks - stops counting when Rx_FEC is not enabled (unknown (1) and disabled (2)). dot3EponFecBufferHeadCodingViolation - stops counting when Rx_FEC is not enabled (unknown (1) and disabled (2)). The object: dot3EponFecAbility - indicates the FEC ability and it is not affected by the dot3EponFecMode object.