“…The SCF, SDF, SSF, CCF and SRF in Figure 1 stand for service control function, service data function, service switching function, call control function and special resource function, respectively. Figure 2 [14] shows the information [14,15] and interfaces related to the SCGF. A path between two interfaces of a gateway or between one interface and an internal point of gateway, through which information such as protocol message flows, is called IFT [14].…”