Method for ensuring network servicequality

Through SGSN, user terminal sends request for activating PDP context to GGSN. After receiving the request, GGSN sends ID information of the service request to PDF. PDF sends application for reserving resources to BCF in load-carrying net. BCF determines whether there is enough resource in the load-carrying net; if yes, resource met to requirement is reserved, and message of successful reserving resources is returned to PDF; otherwise, message of unsuccessful reserving resources is returned to PDF. After receiving message returned from BCF, PDF returns the message to GGSN, and this reservation is ended. Procedure for activating context in packet data protocol is related to resource state in load-carrying net in the invention. When determining whether context in packet data protocol is built, the invention considers resources state on mobile network and load-carrying net so as to guarantee service quality of context in packet data protocol.