Architecture enhancement of digital switching system

Abstract

This paper describes architecture enhancement of the FETEX-150 digital switching system for central office use. The functions provided by central office switch is increasing year by year and enhancement of processing capability is indispensable. Current FETEX-150 architecture is distributed control with three types of processors, namely Main Processor (MPR), Call Processor (CPR) and Line Processor (LPR). In addition various peripheral processors are used. The programs of peripheral processors are downloaded from MPR/CPR/LPR. The software architecture of FETEX-150 is 'hypothetical independent exchange method' which prevents the failure of one processor to propagate to other processors. In order to realize powerful processing capability with high flexibility, multiprocessor ring bus is under development. Optic fiber cable with 100 Mb/s is used and maximum 64 processor pairs can be connected to the bus. FDDI protocol is adopted for Layers 1 and 2 and higher layers are based on OSI. Using this multiprocessor ring bus, various subsystems will be introduced, e.g. Broadband ISDN subsystem Application Processors, etc.