Protocol-Oriented Service Specifications and Their Transformation into CCITT Specification and Description Language

Masaki ITOH

IEICE TRANSACTIONS (1976-1990)   Vol.E69    No.4    pp.524-535
Publication Date: 1986/04/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Switching Systems and Communication Processing

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This paper presents a language called SAL (Service Addition Language) which is used to describe protocol-oriented service specifications for communications software. This language has the following features:
(1) Formal representation of the message sequence diagram: An individual service can be specified in an algebraic form of message sequence diagrams which are widely used in service design.
(2) Separate description of services: New services to be added can be specified without the necessity of referring to the existing services. The synthesizer utility for SAL is prepared to detect any inconsistent relationship between the new and existing services.
(3) Transformability into CCITT SDL (Specification and Description Language) document: As new service specifications are integrated with existing ones, functional specifications in SDL are automatically extended to implement the new along with the existing services. This is also done by the synthesizer.
The algorithm is presented, which detects inconsistent relations between services, and a considerable amount of effort for service addition is shown to be automatable by introducing SAL. SAL and its supporting utilities are intended to be integrated into a development and maintenance environment called a Systems Design Environment (SDE) for communications software. SDE has a utility which generates program codes for the processes defined by the SDL documents which are derived from SAL description.