Message Sequence Charts (MSCs) are a graphical language for scenarios of communicating components exchanging messages in a distributed environment. The language has been standardised by the International Telecommunication Union (ITU) and given a formal semantics by means of a process algebra. Nevertheless, little attention has been given to MSCs where a message with data is a building block. In this paper, we investigate the impact that the concept of data flow brings to the conventional

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... cs, and propose a CCS-like process calculus as an alternative formal framework. The proposed semantics captures the data flow properties while maintaining the expressiveness of the conventional semantics. Equivalence of MSCs is also discussed from the perspective of the corresponding process equivalence.