Extended type systems of action languages for the development of communication protocols

The specification and implementation of communication protocols can be formally done with extended finite state machines. Action languages allow the specification of detailed behavior in the context of activities and state machines. These action languages may define expressions and statements that do evaluations on a specific type system. On the other hand message syntax languages (MSL) are used for the description of the syntax of protocol messages (i.e. encoding and decoding) of communication data. The typical approach of integrating a MSL into an action language is to map the type of the MSL to the action language. This type-mapping approach has limitations if the type system of the action language does not conform with the type declarations that are allowed within the message syntax language. This issue makes it impossible to use different messages syntax languages in the same action language to describe the behavior of communication protocols. In this short paper we present our current work on a model-based engineering (MBE) approach to dynamically integrate type declarations of message syntax languages as the type system of an action language. We discuss our approach in relation to existing technologies around UML, ALF, ASN.1 and SDL and explain our solution based on a simple text based protocol. Furthermore we demonstrate how this new action language can be used for the implementation of communication protocols that are based on state machines.