Drago Žagar, Nino Vrandečić, Antun Stoić

Abstract
As a result of using Information Technology (IT) in different technological processes it is necessary to develop new application specific communication protocols. The number of application specific protocols is growing rapidly in different areas: medicine, communication, industry, power systems, computer networks, etc. Protocol errors discovered in the implementation phase are usually a consequence of inconsistent protocol design, which implies the necessity of methodology for error detection in an early design phase. This paper describes formal methods for distributed systems, especially SPIN/Promela tool for formal verification of logical consistency in distributed systems. A protocol used in power systems IEC60870-5-101 has been verified as an example of formal verification of a distributed system. Formal specification, simulation and verification of logical consistency have been successfully done by using SPIN/Promela software.
Keywords
distributed systems, finite state machine, protocol, validation