SMT-Based Synthesis of Distributed Self-Stabilizing Systems

Abstract

A self-stabilizing system is one that guarantees reaching a set of legitimate states from any arbitrary initial state. Designing distributed self-stabilizing protocols is often a complex task and developing their proof of correctness is known to be significantly more tedious. In this article, we propose an SMT-based method that automatically synthesizes a self-stabilizing protocol, given the network topology of distributed processes and description of the set of legitimate states. Our method can synthesize synchronous, asynchronous, symmetric, and asymmetric protocols for two types of stabilization, namely weak and strong . We also report on successful automated synthesis of a set of well-known distributed stabilizing protocols such as Dijkstra’s token ring, distributed maximal matching, graph coloring, and mutual exclusion in anonymous networks.

Automation of fault-tolerant graceful degradation

“…Even though the addition of fault tolerance (FT) is NPcomplete in the size of the state space, it has been shown to be feasible to add FT to programs of moderate size [24], up to programs with state space of 10 100 [25]. However, the approach may not directly scale to C++ programs of 1000s of lines of code.…”

Specification-Based Synthesis of Distributed Self-Stabilizing Protocols

“…Our technique is inspired by our SMT-based method in [14]. In particular, we transform the problem input into an SMT instance.…”

“…SMT constraints appear in Subsections 6.2-6.3. Note that using our approach in [14], we can synthesize different systems considering types of timing models (i.e., synchronous and asynchronous), symmetric and asymmetric, as well as strong-and weak-stabilizing protocols. Example.…”

“…Motivation. Recently, Faghih and Bonakdarpour [14] proposed a sound and complete method to synthesize finite-state self-stabilizing systems based on SMT-solving. However, the shortcoming of this work as well as the techniques in [4,10,22] is that an explicit description of LS is needed as an input to the synthesis algorithm.…”

Επιδιόρθωση Συστημάτων Μεταβάσεων Μέσω Αφαίρεσης

“…Finally, a slightly dierent but also related problem is that of Model Revision, which has been studied for UNITY properties in [16,18] and for CTL in [58]. Other methods in the area of fault-tolerance include the work in [52], which uses discrete controller synthesis and [50], which employs SMT solving. Another interesting work in this direction is in [47], where the authors present a repair algorithm for fault-tolerance in a fully connected topology, with respect to a temporal specication.…”