Abstract: This application provides a packet sending method, a device, and a system, and belongs to the field of EVPN technologies. In the solutions provided in this application, when a DF device switches from a first PE device to a second PE device due to a fault in a link between the first PE device and a CE device, the first PE device may send a first packet to the second PE device, so that the second PE device forwards the first packet to the CE device. Therefore, the CE device may generate or update a MAC entry in time based on the first packet forwarded by the second PE device, and may send a packet to the second PE device based on the MAC entry. In this way, the second PE device that switches to the DF device may forward the packet from the CE device, so that normal forwarding of uplink traffic sent from the CE device can be ensured, and interruption of the uplink traffic of the CE device can be avoided.

Abstract: A method for sending a BIERv6 (bit index explicit replication version 6) packet includes: determining, by a first network device, that an active next-hop device for reaching a second network device is faulty, where the first network device belongs to a first area in a BIER domain, the second network device and the active next-hop device belong to a second area in the BIER domain, the active next-hop device is a border device in the second area and is configured to connect to the first area, and the first area and the second area have different protocols; and sending, by the first network device, a BIERv6 packet to a backup next-hop device for reaching the second network device, where the backup next-hop device is a border device in the second area and is configured to connect to the first area.

Abstract: This application provides a method for sending a BIERv6 packet and a first network device. The method includes: determining, by a first network device, that an active next-hop device for reaching a second network device is faulty, where the first network device belongs to a first area in a BIER domain, the second network device and the active next-hop device belong to a second area in the BIER domain, the active next-hop device is a border device in the second area and is configured to connect to the first area, and the first area and the second area have different protocols; and sending, by the first network device, a BIERv6 packet to a backup next-hop device for reaching the second network device, where the backup next-hop device is a border device in the second area and is configured to connect to the first area.