Path-based protocol verification approach

Abstract

Protocol verification is one of the most challenging tasks in the design of protocols. Among the various proposed approaches, the one based on reachability analysis (or known as state enumeration approach) is of the most simple, automatic and effective. However, the state explosion problem is a principle obstacle toward successful and complete verifications of complex protocols. To overcome this problem, we proposed a new approach, the “path-based approach.” The idea is to divide a protocol into a collection of individual execution record, denoted as concurrent paths, a partial order representation recording the execution paths of individual entities. Then, the verification of the protocol is, thus, replaced by that of individual concurrent paths. Since concurrent paths can be automatically generated through Cartesian product of the execution paths of all modules, and verified independently, the memory requirement is limited to the complexity of individual concurrent path rather than the whole protocol. Thus, the state explosion problem is alleviated from such “divide and conquer” approach. Furthermore, we propose an algorithm, making the trade-off on memory requirement to generate the concurrent paths more efficiently; and utilize the technique of symmetric verification, parallel computing to improve the efficiency of verification. Eventually, our experience of verifying real protocols shows that our approach uses much less memory and time than reachability analysis.