Instruction manual

FUNCTIONAL DESCRIPTION
Memory Allocation
The system software, like the hardware, is identified by release and version number. Each
version identifies a particular memory configuration for the release number. Main memory is
located in the Common Control circuitry, that is, the CPU/MEM Circuit Pack.
Real-Time Constraints
Real-time constraints are a function of the speed of the common control circuitry and the
traffic load. The switch is designed so that many time-consuming and repetitious functions
are performed by processors in the port and service circuit packs, thus relieving the common
control circuits.
Traffic load, defined as the sum of static and dynamic loads, is a function of the number of
features that are executed, the frequency with which they are executed, the system
configuration,
and the instantaneous (peak) call processing load. The configuration
contribution to load is known as dynamic load. The static load consists of maintenance and
audit routines.
Software Partitioning
As shown in Figure 3-21, System 25 software is comprised of various modules, each
supporting a particular process. Typical modules (referred to as tasks) include the following:
● Administration
● Station Call Processing
● Station Message Detail Recording (SMDR) Call Record Processing
● Trunk Call Processing
● Dial Plan Manager
● Event Timer
● Save/Restore (Administration function)
● Maintenance and Audit Functions.
Specific software tasks are associated with the memory and call processing portions of the
CPU/MEM, the TDM Bus, and the Port Circuits.
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