Non-Stop Service-Enhanceable Communications Software Platform Based on an Object-Oriented Paradigm

Keiichi KOYANAGI  Tetsuyasu YAMADA  Hiroshi SUNAGA  Akira OKAMOTO  Michihiro MONDEN  

IEICE TRANSACTIONS on Communications   Vol.E78-B   No.7   pp.1043-1055
Publication Date: 1995/07/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Communication Software
object-oriented,  non-stop technology,  C++,  switching program,  

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This paper presents a layered hierarchical switching-software technology, which is based on an object-oriented design approach, that improves 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 features without interrupting service, and which improves software reliability. This technology was developed as part of our overall plan to establish a communications software platform that can be customized for use by various communications systems, such as STM, ATM, and IN. The developed non-stop service enhanceable software techniques are call-recovery restart, system file update, and on-line partial file modification; they were achieved by using dynamic program modification. A system file update inevitably affects calls in service, despite efforts to save in-service calls by copying the call data from the old file to the new one. We have therefore developed a different approach: on-line partial-file modification. Our prototype switching system has proven the effectiveness of this modification method and has shown that it can cover a limited range of service feature additions (which meets customer demands for quick service provisioning), as well as all bug fixes (which can lead to higher software reliability due to not using conventional machine code for software patching), without interrupting service. This paper describes on-line partial-file modification, which can be applied to communications systems that require resident program modification 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 about two times and that the total increase in systems development productivity is about 25%.