Verifying a smart design of TCAP a synergetic experience

An optimisation of the SS No. 7 Transport Capabilities Procedures is veri ed by specifying both the original and the optimised TCAP in CRL, generating transition systems for both using the CRL tool set, and checking weak bisimulation equivalence of the two using the C sar/Ald ebaran tool set, these steps being part of a iterative process of speci cation, re nement and veri cation. As a result, the optimisation design is debugged, a deeper understanding of the protocol is gained, and the usability of the CRL tool set is evaluated. In conclusion, the design of an optimised TCAP indeed bene tted from the veri cation reported here, and CRL and C sar/Ald ebaran appeared to be a largely adequate combination for the veri cation at hand; however, since the characteristics of TCAP were not explicit from the start, and the tools used covered the functionality required not perfectly, the veri cation required a good deal of human ingenuity and stamina. 1991 Mathematics Subject Classi cation: 68Q60 Speci cation and veri cation of programs 1991 Computing Reviews Classi cation System: B4.4 Performance analysis and design aids; D.2.1 Requirements/Speci cations; D.2.4 Program Veri cation