In the proposed architecture, switching system hardware resources are allocated at the equipment level rather than at the component level of LSI chips. Equipment using these resources can thus be shared between independent systems. The efficiency of system development is improved by using structural elements called functional blocks (FBs). The hardware in each FB consists of a shared part (amicroprocessor, its peripheral circuitry, and memory) and a dedicated part that implements the specific functions of the FB. Firmware loaded into the microprocessor consists of a shared part and a dedicated part that corresponds to the hardware parts. Each FB also has its own built-in autonomous testing function to test the reliability of that FB and has its own identification function. By combining these FBs, this approach can flexibly cope with various switching system configurations for plain old telephone service (POTS), integrated services digital network (ISDN), and broad-band ISDN (B-ISDN). Tests using several types of FBs showed that the shared hardware and firmware parts of an FB can be shared between blocks. An architecture based on FBs results in a platform that can handle the hardware for various systems, making it easy to construct new switching systems.

A service control node in the Advanced Intelligent Network (AIN) allocates data for customers among multiple modules and performs distributed processing of multiple transactions. In such a node, load can vary among the modules due to dispersion in the amount of traffic for each customer. It is therefore important to balance out this load variation and raise the utilization of each module in order to achieve an efficient distributed processing system. We first propose a method for balancing the load among modules by dynamically transferring customer data in units of records from high-load modules to low-load modules. Then, based on this method, a method for selecting records to be transferred between modules is also proposed. And we clarify the processor overhead for transferring records. The effect of the reduction of number of modules by load balancing is also evaluated. Based on the these results, it is shown that dynamic transferring of records is an effective scheme for balancing load among modules in a service control node of the AIN.