Specification of an ISDN Q.931 protocol entity using the LOTOS formal description technique

A description is presented of the formal specification and implementation of the D-channel layer-3 protocol used in the user-network interface of the integrated services digital network. This protocol is informally defined in the CCITT Recommendation Q.931. The formal description technique LOTOS has been used to formalize this definition and to derive a Q.931 protocol implementation in C language, using semi-automatic tools. The resulting Q.931 implementation will be integrated in a prototype integrated services private branch exchange which is being developed in the DAMS (Dynamically Adaptable Multiservice System) project within the ESPRIT program.<
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