The definition of data stream is given, based on which the time-delay model for Internet network control
system(INCS) is proposed theoretically for both TCP and UDP protocol. The definition of data stream describs the
input characteristics and output charactersitics for all the data streams. The time-delay model describes the time-delay
characteristics for TCP and UDP protocol. The time-delay measurement model for INCS is proposed based on Transit-Stub.
Experiment results show the validity of time-delay model. As a result, theoretical basis is provided for designing an INCS.