A forwarding table generation method is provided. The method includes: determining, by a forwarding device, a first timeslot set, where the first timeslot set includes multiple timeslots during which the forwarding device sends, to a first device by using a first flexible Ethernet group, multiple encoded data blocks generated by a physical coding sublayer; determining, by the forwarding device, a second timeslot set, where the second timeslot set includes multiple timeslots during which the forwarding device receives, by using a second FlexE group, the multiple encoded data blocks sent by a second device; and generating, by the forwarding device, a forwarding table, where the forwarding table includes a mapping relationship between the second FlexE group and the multiple timeslots included in the second timeslot set, and between the first FlexE group and the multiple timeslots included in the first timeslot set.