A method of providing seamless quality of service (QoS) guarantees, which is performed by a network control unit to control a network connecting unit for connecting a terminal to a service network, when an Internet Protocol (IP)-based mobility service is provided, comprising:
- when a terminal performs handover, recognizing that a network connecting unit in which the terminal has been registered is changed to a different network connecting unit;
- and
- providing QoS information of the terminal to the different network connecting unit.