A mobility management network element, wherein the network element comprises: a processor, and a memory, a receiver, and a transmitter that are electrically connected to the processor, wherein the receiver is configured to receive a connection establishment request of a terminal, wherein the connection establishment request carries user location information of the terminal; the processor is configured to control the transmitter to send the connection establishment request to a packet data gateway; the receiver is configured to receive an IP address of the terminal that is fed back by the packet data gateway, wherein the IP address is assigned by the packet data gateway to the terminal according to a correspondence between the user location information and an IP address pool; the processor is further configured to control the transmitter to send the IP address to the terminal, characterized in that the processor is further configured to: if the terminal leaves a current location area and enters a target location area, determine, according to a location area change of the terminal, whether to control the transmitter to send a release request to the terminal; if the current location area and the target location area are both managed by the mobility management network element, and the target location area does not correspond to any IP area, control the transmitter to send the release request to the terminal; the processor is further configured to: if the current location area and the target location area are both managed by the mobility management network element, and the target location area belongs to another IP area, control the transmitter to send the release request to the terminal; or the processor is further configured to skip sending the release request to the terminal if the current location area and the target location area are both managed by the mobility management network element, and the current location area and the target location area belong to a same IP area, wherein each IP area corresponds to one or more than one IP address pool. if the terminal leaves a current location area and enters a target location area, determine, according to a location area change of the terminal, whether to control the transmitter to send a release request to the terminal; if the current location area and the target location area are both managed by the mobility management network element, and the target location area does not correspond to any IP area, control the transmitter to send the release request to the terminal; the processor is further configured to: if the current location area and the target location area are both managed by the mobility management network element, and the target location area belongs to another IP area, control the transmitter to send the release request to the terminal; or the processor is further configured to skip sending the release request to the terminal if the current location area and the target location area are both managed by the mobility management network element, and the current location area and the target location area belong to a same IP area, wherein each IP area corresponds to one or more than one IP address pool.