Verifying the Leader Election Algorithm in GROOVE

In this paper we present how the leader election protocol specified in [1] was modelled with the GROOVE tool set. The goal of this protocol is to find the smallest of a set of uniquely numbered processes arranged in a ring, without having a central controller available. GROOVE is a graph transformation tool, which uses directed simple graphs with labelled edges. In the remainder of this article, first we introduce GROOVE in the next section. Then we define the different variants of the problem in Section 3. We propose three different scenarios, gradually more complex, in Sections 4, 5 and 6. In Section 4 we assume that the processes are synchronised and they all generate their messages in the beginning of the algorithm. In Section 5 this constraint is removed and processes can send their initial message at any time. In Section 6 we present a generalised version of the problem, where processes can dynamically enter and leave the network. We show how we verified these three scenarios in Section 7. The experimental results are given in Section 8. Finally, Section 9 concludes.