Backup Designated Router (BDR) election and Designated Router (DR) failure processing methods and equipment are provided. When a user joins, a BDR in a subnetwork completes a preparation for forwarding multicast traffic for the user, but does not forward the multicast traffic through an interface; and when detecting that a DR in the subnetwork fails, the BDR is switched to be a DR in the subnetwork, and forwards the multicast traffic for the user through the interface.