Abstract: The present invention discloses a method for informing Home Subscriber Server (HSS) of Packet Data Network Gateway (PDN GW) address information to be stored in the HSS in the System Architecture Evolution. The method comprises: the Mobility Management Node acquires that the PDN GW address information is not stored in the HSS, or the Mobility Management Node selects another PDN GW; the Mobility Management Node informs the HSS of the PDN GW address information to store. According to the present invention, the HSS can obtain the PDN GW address information directly from the MME without the help of the 3GPP AAA Server and the roaming interface between the PDN GW and the HSS.

Abstract: A method for avoiding resource being released mistakenly during tracking area update or handover process comprising: determining, by a target Mobility Management Entity MME, whether to use an old System Architecture Evolution Serving GW or to reselect a new Serving GW; if the target MME determines to select a new serving GW, notifying the original MME, the original MME sending a request for deleting bearer to the old Serving GW. The technical scheme of the present invention can avoid that the original MME will still send a request for deleting subscriber context to the old Serving GW when the target MME still uses the old Serving GW rather than selects a new one during tracking area update or handover process of the subscriber, which results in the appearance of a problem that the resource related to the subscriber in the old Serving GW is released mistakenly.