A method for mobility management includes: initiating a flow of accompany migration or handover to a target cell controlled by a primary Radio Network Controller (RNC) of a Drift Radio Network Controller (DRNC) (101); if the target cell controlled by the primary RNC has switched to a spare RNC of DRNC, receiving a failure response returned from the primary RNC, and said failure response carrying information of the target cell controlled by the spare RNC or indication information for obtaining information of the target cell controlled by spare RNC (102); initiating accompany migration or handover to the target cell controlled by said spare RNC according to said target cell information or the indication information (103). The present invention also provides a network device, an RNC and a communication system.
