NONSTOP SERVICE-ENHANCEABLE COMMUNICATIONS SOFTWARE PLATFORM BASED ONAN OBJECT-ORIENTED PARADIGM

This paper presents a layered hierarchical switching-software technolo gy, which is based on an object-oriented design approach, that improve s software reusability and productivity. This technology enables a non -stop, service-enhanceable software environment (called NOSES), which satisfies customer demands for quick provisioning of new service featu res without interrupting service, and which improves software reliabil ity. This technology was developed as part of our overall plan to esta blish a communications software platform that can be customized for us e by various communications systems, such as STM, ATM, and IN. The dev eloped non-stop service enhanceable software techniques are call-recov ery restart: system file update, and on-line partial file modification ; they were achieved by using dynamic program modification. A system f ile update inevitably affects calls in service, despite efforts to sav e in-service calls by copying the call data from the old file to the n ew one. We have therefore developed a different approach: on-line part ial-file modification. Our prototype switching system has proven the e ffectiveness of this modification method and has shown that it can cov er a limited range of service feature additions (which meets customer demands for quick service provisioning), as well as all bug fixes (whi ch can lead to higher software reliability due to not using convention al machine code for software patching), without interrupting service. This paper describes on-line partial-file modification, which can be a pplied to communications systems that require resident program modific ation or initialization without program loading; that is, the program exists permanently in main memory. An evaluation of this approach also showed that the productivity of service-layer software increases abou t two times and that the total increase in systems development product ivity is about 25%.