A method, a system, or an article of manufacture provides Mobility Management (MM), for example, an update procedure, in a Core Network (CN) of a mobile communication system. The Mobile Station (MS) includes an indicator which defines an update type. The update type includes: all CN entities; one type of CN entity only. If the indicator has the update type of all CN entities, the MS registers all CN entities. If the indicator has the update type of one type of CN entity only, the MS registers the one type of CN entity only. The CN entities may be MSC/NVLR CN entity, SGSN CN entity, or other CN entity. The method includes the MS determining to which of the CN entity to perform the update procedure; the MS updating the CN entity; the CN acknowledging the MS whether update is successful or failed; and the CN acknowledging the MS whether update of other CN entity is needed, if needed, the CN defining to which of the CN entity to perform update, and continuing the update of the defined CN entity. The MS does not have to know the services subscribed to a user, nor does the MS have to know the configuration of the CN.