A telecommunication feature is an optional or incremental unit of functionality, such as call display (CD) and call forwarding (CF). A feature interaction occurs when, in the presence of other features, the actual behavior of a feature becomes inconsistent with its specified behavior. This feature interaction problem is a long-existing problem in telephony, and it becomes an increasingly pressing problem as more and more sophisticated features are developed and put into use. It takes a lot of effort to test that the addition of a new feature to a system doesn???t affect any existing features in an undesired way. Distributed Feature Composition (DFC) proposed by Michael Jackson and Pamela Zave, is an architectural approach to the feature interaction problem. Telecommunication features are modeled as independent components, which we call boxes. Boxes are composed in a pipe-and-filter-like sequence to form an end-to-end call. Our work studies the behaviour of single feature boxes. We translate BoxTalk specifications into another format, that is more conducive to automated reasoning. We build formal models on the translated format, then the formal models are checked by a model checker, SPIN, against DFC compliance properties written in Linear Temporal Logic (LTL). From BoxTalk specifications to Promela models, the translation takes steps: 1) Explicating BoxTalk, which expands BoxTalk macros and presents its implicit behaviours as explicit transitions. 2) Define BoxTalk semantics in terms of Template Semantics. 3) Construct Promela model from Template Semantics HTS. Our case studies exercised this translation process, and the resulting models are proven to hold desired properties.

A telecommunication feature is an optional or incremental unit of functionality, such as call display (CD) and call forwarding (CF). A feature interaction occurs when, in the presence of other features, the actual behavior of a feature becomes inconsistent with its specified behavior. This feature interaction problem is a long-existing problem in telephony, and it becomes an increasingly pressing problem as more and more sophisticated features are developed and put into use. It takes a lot of effort to test that the addition of a new feature to a system doesn’t affect any existing features in an undesired way. Distributed Feature Composition (DFC) proposed by Michael Jackson and Pamela Zave, is an architectural approach to the feature interaction problem. Telecommunication features are modeled as independent components, which we call boxes. Boxes are composed in a pipe-and-filter-like sequence to form an end-to-end call. Our work studies the behaviour of single feature boxes. We translate BoxTalk specifications into another format, that is more conducive to automated reasoning. We build formal models on the translated format, then the formal models are checked by a model checker, SPIN, against DFC compliance properties written in Linear Temporal Logic (LTL). From BoxTalk specifications to Promela models, the translation takes steps: 1) Explicating BoxTalk, which expands BoxTalk macros and presents its implicit behaviours as explicit transitions. 2) Define BoxTalk semantics in terms of Template Semantics. 3) Construct Promela model from Template Semantics HTS. Our case studies exercised this translation process, and the resulting models are proven to hold desired properties.

Telecommunication systems are structured to enable incremental growth, so that new telecommunication features can be added to the set of existing features. With the addition of more features, certain existing features may exhibit unpredictable behaviour. This is known as the feature interaction problem, and it is very old problem in telecommunication systems. Jackson and Zave have proposed a technology, Distributed Feature Composition (DFC) to manage the feature interaction problem. DFC is a pipe-and-filter-like architecture where features are "filters" and communication channels connecting features are "pipes". DFC does not prescribe how features are specified or programmed. Instead, Zave and Jackson have developed BoxTalk, a call-abstraction, domain-specific, high-level programming language for programming features. BoxTalk is based on the DFC protocol and it uses macros to combine common sequences of read and write actions, thus simplifying the details of the DFC protocol in feature models. BoxTalk features must adhere to the DFC protocol in order to be plugged into a DFC architecture (i.e., features must be "DFC compliant"). We want to use model checking to check whether a feature is DFC compliant. We express DFC compliance using a set of properties expressed as linear temporal logic formulas. To use the model checker SPIN, BoxTalk features must be translated into Promela. Our automatic verification process comprises three steps: 1. Explicate BoxTalk features by expanding macros and introducing implicit details. 2. Mechanically translate explicated BoxTalk features into Promela models. 3. Verify the Promela models of features using the SPIN model checker. We present a case study of BoxTalk features, describing the original features and how they are explicated and translated into Promela by our software, and how they are proven to be DFC compliant.

Telecommunication systems are structured to enable incremental growth, so that new telecommunication features can be added to the set of existing features. With the addition of more features, certain existing features may exhibit unpredictable behaviour. This is known as the feature interaction problem, and it is very old problem in telecommunication systems. Jackson and Zave have proposed a technology, Distributed Feature Composition (DFC) to manage the feature interaction problem. DFC is a pipe-and-filter-like architecture where features are "filters" and communication channels connecting features are "pipes". DFC does not prescribe how features are specified or programmed. Instead, Zave and Jackson have developed BoxTalk, a call-abstraction, domain-specific, high-level programming language for programming features. BoxTalk is based on the DFC protocol and it uses macros to combine common sequences of read and write actions, thus simplifying the details of the DFC protocol in feature models. BoxTalk features must adhere to the DFC protocol in order to be plugged into a DFC architecture (i.e., features must be "DFC compliant"). We want to use model checking to check whether a feature is DFC compliant. We express DFC compliance using a set of properties expressed as linear temporal logic formulas. To use the model checker SPIN, BoxTalk features must be translated into Promela. Our automatic verification process comprises three steps: 1. Explicate BoxTalk features by expanding macros and introducing implicit details. 2. Mechanically translate explicated BoxTalk features into Promela models. 3. Verify the Promela models of features using the SPIN model checker. We present a case study of BoxTalk features, describing the original features and how they are explicated and translated into Promela by our software, and how they are proven to be DFC compliant.