A network-based mobility management system in which mobility management for a mobile terminal is not performed by the mobile terminal but is performed on a network side, the network-based mobility management system comprising: a plurality of mobility anchors including first and second mobility anchors, each of the plurality of mobility anchors being configured to transmit and receive a data packet to and from an external network; at least one access gateway including a first access gateway, the at least one access gateway being disposed between the mobile terminal and the plurality of mobility anchors, each of the at least one access gateway being configured to transmit and receive data packets to be transferred between the mobile terminal and the external network to and from at least one of the plurality of mobility anchors; and mobility management control means for controlling switching of a mobility anchor that transfers the data packets, wherein the mobility management control means is configured to send, to the first access gateway, a transmission-path control signal for changing a route of only a part of a data packet flow that pertains to the mobile terminal and is originally transferred through the first access gateway and the first mobility anchor, so as to be transferred through the second mobility anchor, and the first access gateway is configured to i) establish, between the first access gateway and the second mobility anchor, a logical transmission path for transferring the part of the data packet flow, in response to receiving the transmission-path control signal, and ii) transmit the part of the data packet flow to the second mobility anchor and also transmit a remaining part of the data packet flow to the first mobility anchor by distinguishing a data packet received from the mobile terminal. a plurality of mobility anchors including first and second mobility anchors, each of the plurality of mobility anchors being configured to transmit and receive a data packet to and from an external network; at least one access gateway including a first access gateway, the at least one access gateway being disposed between the mobile terminal and the plurality of mobility anchors, each of the at least one access gateway being configured to transmit and receive data packets to be transferred between the mobile terminal and the external network to and from at least one of the plurality of mobility anchors; and mobility management control means for controlling switching of a mobility anchor that transfers the data packets, wherein the mobility management control means is configured to send, to the first access gateway, a transmission-path control signal for changing a route of only a part of a data packet flow that pertains to the mobile terminal and is originally transferred through the first access gateway and the first mobility anchor, so as to be transferred through the second mobility anchor, and the first access gateway is configured to i) establish, between the first access gateway and the second mobility anchor, a logical transmission path for transferring the part of the data packet flow, in response to receiving the transmission-path control signal, and ii) transmit the part of the data packet flow to the second mobility anchor and also transmit a remaining part of the data packet flow to the first mobility anchor by distinguishing a data packet received from the mobile terminal.