A component-based design and compositional verification of a fault-tolerant multimedia communication protocol

Component-based software engineering is increasingly being adopted in developing a wide range of applications that have high dependability requirements. Continuing along with our ongoing efforts in developing a framework integrating the concepts of component-based design for fault-tolerance and category-theory-based modular composition, in this paper, we present a component-based design of a fault-tolerant multimedia protocol and composition of resulting components through correct-by-construction approach. Essentially, we show how a fault-intolerant program is transformed into a fault-tolerant program with components providing for dependability, namely, detectors and correctors. We first show the correctness of the fault-tolerant program, and then to achieve a rigorous composition out of the fault-intolerant program and fault-tolerant components, we utilize concepts of category theory to develop component-based fault-tolerant program. We illustrate the overall development of a fault-tolerant program with a case study of the label distribution protocol (LDP). The compositional specification and its correctness for the FT-LDP has been realized through a mechanized formal tool called Specware.