Methods and related devices for implementing disaster recovery

A method for implementing disaster recovery, comprising:

• receiving, by a User Plane Function (UPF), a first request sent by a backup Session Management Function (SMF), wherein the first request carries a node identifier (Node ID) of a main SMF, a Node ID of the backup SMF, and a Common Session endpoint Identifier List (CSIDLIST) corresponding to the backup SMF, a session or sessions in the CSIDLIST corresponding to the backup SMF is/are the same as session or sessions in a CSIDLIST corresponding to the main SMF or is/are a part of the session or sessions in the CSIDLIST corresponding to the main SMF, and the first request is used for notifying the UPF that the main SMF fails and the session or sessions in the CSIDLIST corresponding to the backup SMF is/are to be taken over by the backup SMF;
• and recording, by the UPF, a correspondence table between the main SMF and the backup SMF according to the first request, and subsequently interacting, by the UPF, with the backup SMF for the session or sessions in the CSIDLIST corresponding to the backup SMF, wherein the correspondence table comprises a state of the main SMF, the backup SMF corresponding to the main SMF, and the CSIDLIST corresponding to the backup SMF;
• or,
• receiving, by the UPF, a third request sent by a main SMF, wherein the third request carries a Node ID of the main SMF, a Node ID of a backup SMF, and a CSIDLIST corresponding to the main SMF, and the third request is used for notifying the UPF that the main SMF recovers from a failure and a session or sessions in the CSIDLIST corresponding to the main SMF is/are to be taken over by the main SMF;
• and setting, by the UPF, a state of the main SMF in a correspondence table between the main SMF and the backup SMF to normal according to the third request, and subsequently interacting, by the UPF, with the main SMF for the session or sessions in the CSIDLIST corresponding to the main SMF, wherein the correspondence table comprises the state of the main SMF, the backup SMF corresponding to the main SMF, and the CSIDLIST corresponding to the backup SMF, and the session or sessions in the CSIDLIST corresponding to the backup SMF is/are the same as session or sessions in the CSIDLIST corresponding to the main SMF or is/are a part of the session or sessions in the CSIDLIST corresponding to the main SMF.