AN ESTELLE-BASED INCREMENTAL PROTOCOL DESIGN SYSTEM

Formal description techniques (FDTs) provide formal and abstract ways to specify what protocols have to do and what features protocols need. Estelle is an FDT defined by the International Organization for Stand ardization for protocol specifications. We present an incremental prot ocol design system that contains an incremental protocol verification technique and an Estelle translator. Our incremental protocol design s ystem allows on-line reverification after respecification. That is, in stead of verifying respecified (modified) protocols from scratch, the reverification procedure is executed continuously and incrementally at the modification point. Using the translator, Estelle protocol specif ications can be translated and interpreted for protocol verification. To meet the requirement of modifying protocol specifications written i n Estelle at run time, the Estelle translator allows incremental trans lation and interpretation of the modified Estelle specification part f or incremental verification. To further reduce the number of global st ates to be explored, the concept of dead and live variables is incorpo rated into our incremental verification technique. Based on the increm ental verification technique and the Estelle translator, an incrementa l protocol design system (IPDS) is developed on SUN SPARC OPENLOOK wor kstations. Using IPDS, protocol designers can analyze the verification results, interactively modify the protocols, and then continue the ve rification incrementally. (C) 1997 by Elsevier Science Inc.