Reliable, reusable Ada components for constructing large, distributed multi-task networks: networks architecture services (NAS)

This paper will introduce the key concepts of TRW's Reusable Message Based Design Software (Network Architecture Services- NAS) which has proven to be key to the CCPDS-R project's progress to date. The NAS software and supporting tools have provided the CCPDS-R Project team with reliable, powerful building blocks that have been integrated into extensive demonstrations to validate the critical design approaches. The CCPDS-R PDR Demonstration consisted of 130 Ada tasks interconnected via 450 different task to task interfaces, executing in a network of 3 VAX nodes. The extensive reuse of NAS software building blocks and Ada generics resulted in the translation of 120,000 Ada Source lines into over 2 million lines of executable machine language instructions. The NAS software (about 20,000 Ada source lines) was conceived in a TRW Independent Research and Development project in 1985, and has since been refined and evolved into a truly reusable state. Although NAS reuse is limited currently to Digital Equipment Corporation VAX VMS networks, efforts are underway to provide heterogeneous NAS capabilities.