Transfer of Cyclades Applications Towards Transpac Network One Solution: The ST3 Software

Abstract

This paper describes a part of a research work made at ESE under contract with CNET (Centre National d’Etudes des Télécommunications) through CCETT (Centre Commun d’Etudes de Television et de Telecommunications). Its purpose was to define and implement ST3, an experimental Network Control Program (NCP) for the TRANSPAC network, in order to offer the same users network access as featured into ‘ST2’ the NCP implemented by IRIA and CII-HB for the CYCLADES network.

ST2 and ST3 should be simultaneously accessible in a same computer used as an experimental gateway between the two networks at applications level. ST3 was to match the most of ST2 into X25 features. It seemed interesting to divide ST3 into an X25 ‘transport station’ (STX25) and an ‘interface converter’.

STX25 offers to users’ programs an acces to X25 facilities, with ‘message’ (letter) management and additionnal subaddressing. The STX25 user’s interface and structure is widely drawn from ST2. If one accepts the loss of some particular details of ST2, the interface converter became fairly easy to implement.

This software is implemented on CCETT’s IRIS 80 computer, using LAP/ECMA link acces protocol.