Study and design of IN/Internet interworking model

Referring to IN/Internet interworking models proposed by ITU-T and PINT (PSTN/Internet interworking) respectively, another model is designed here based on the CIN (Chinese intelligent network) system of BUPT (Beijing University of Posts and Telecommunications). This model carries out heavy modifications and refinements on those two reference models. Before discussion, this model is divided into three layers horizontally and three sections vertically. Because of the importance of each gateway, emphases are put on them especially. Moreover, a novel concept called "information flow trail" is proposed, which is useful in designing most of the gateways.