2.2. Architecture Overview

Figure 9 is a high level view of the Global Call software architecture and shows how Global Call is used to provide a common call control interface for a variety of network interface technologies including E-1 CAS, T-1 Robbed Bit, analog, ISDN, R4 on DM3, and SS7.

Figure 9. Global Call Architecture

Multiple interface technologies can be mixed within a single application, allowing for example the connection to ISDN and SS7 trunks.

See the Global Call API Programming Guide for more information about the overall Global Call architecture.

For SS7, Global Call requires integration with the DataKinetics environment. The environment is based on a number of communicating modules. Each module is a separate task, process, or program (depending on the operating system type) and has a unique identifier called a module ID. Modules communicate with each other by sending and receiving messages. Each module has a message queue for the reception of messages. This process is called Inter Process Communication (IPC). See the DSC131/DSC231 User's Manual and the SS7 Programmer's Manual for PCCS6 or the SS7 Programmer's Manual for SPCI4, SPCI2S and CPM8 for more information on the software environment and the System7 Software Environment Programmer's Manual for more information on IPC.

Global Call SS7 extends this architecture by providing an Intel® Dialogic SS7 server module (with a configurable module ID, typically 0x4d) that can communicate with existing modules. Applications that use Global Call SS7 are also assigned a module ID in the system. This assignment is automatically made by the SS7 server. An example of interaction of the Global Call SS7 software components is shown in Figure 10.

Figure 10. Global Call SS7 Architecture

As shown in the figure, multiple applications can simultaneously use Global Call SS7, provided they do not attempt to control the same line devices (circuits).

The SS7 Call Control Library is called Libgcs7 and is responsible for the communication with other SS7 components in the system. Consequently, an application using Global Call SS7 does not have to care about any of the lower-level aspects and can be written to the standard Global Call API irrespective of the interface to the SS7 stack, hardware, or communication mechanisms being used. The integration with the actual SS7 stack software environment and the hardware only requires attention during the configuration phase.

For SS7, a Global Call line device maps directly to a telephony circuit in the PSTN. Calls made or received on a circuit are assigned a Call Reference Number (CRN) that is used between the application and the Global Call software to identify the call, just like any other Global Call network interface technology.

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