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2.4 About Ports and Contexts
- Ports are the fundamental objects upon which AG Access operates. A port contains physical and logical resources on the AG board. Ports are typically connected to the telephone network (PSTN), and are used to process calls. A port is represented by a context handle (ctahd).
- AG Access manages the following resources on a per-port basis:
- DSP resources on the AG board.
- Assignment of MVIP streams and timeslots. Depending upon the MVIP
mode selected when opening the port, up to four timeslots may be allocated
to the port, which may include:
- Output signaling (out-of-band) stream
- Input voice (inband) stream
- Output voice (inband) stream
- A context handle, obtained from the adiOpenPort function, addresses an AG Access port and the associated MVIP stream(s). The application subsequently supplies the handle when invoking AG Access functions. Events communicated back to the application are also associated with this handle. See Section 10.2.2 for more detailed information on ports.
- An AG Access port does not encompass the MVIP switching element, as illustrated in Figure 2. The port receives its input from MVIP streams but the switch will be controlled by software outside the scope of AG Access. For example, the NMS SwitchPath(TM) product can be used to route data between the MVIP bus and the port's DSP.
- As depicted in Figure 2, AG Access internal data is within the application process context. This has ramifications with respect to reentrancy and spawning processes and is discussed in Section 10.5.
Figure 2. AG Access Port
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