Correctness of the Chord protocol

Abstract

Internet of Things (IoT) can be seen as a cooperation of various devices with limited performances that participate in the same system. IoT devices compose a distributed architecture system. The core of every IoT system is its discovery and control services. To realize such services, some authors used the developed solutions from the different domains. One such solution is the Chord protocol, one of the first, the simplest and the most popular distributed protocols. Unfortunately, the application of the Chord protocol was realized using the correctness of the Chord protocol for granted, or by the very hard assumptions. In this paper we prove the correctness of the Chord protocol using the logic of time and knowledge with the respect to the set of possible executions, called regular runs. We provide the deterministic description of the correctness of the Chord protocol and consider Chord actions that maintain ring topology while the nodes can freely join or leave.

Complete formal verification of the PSTM transaction Scheduler

“…"Model checking is a technique for automatic verification of software and reactive system, and it consists of verifying some properties of the model of the system", see [7]. We selected three recent papers in order to illustrate formal verification state of the art [4], [5], and [6].…”

“…The paper [4] was motivated by the importance of the discovery and control service of an IoT system based on the Chord protocol, and the obvious fact that errors in concurrent systems are difficult to reproduce and find using solely program testing. The authors manually proved the correctness of the Chord protocol using the logic of time and knowledge with the respect to the set of possible executions (that maintain ring topology while the nodes can freely join or leave).…”

“…However, as this paper shows, conducting traditional formal verification in two steps (described above) as was, for example, done in [1], [4], [5], and [6] is not sufficient. As will be elaborated in more detail in Section 1.1 (related work), the main problem with the traditional two-steps formal verification is that the formal model constructed in the first step is not directly tested.…”

Federating digital contact tracing using structured overlay networks

“…We also provide a brief review of Abstract State Machines, since they are used for proving properties of Chord. For more details, please see [7,16,21,23,25,31,32].…”

“…The correctness and efficiency of the Chord's protocol lookup procedure was in the focus of several papers, e.g. [23,25,31,32]. In [11] the authors exploited the benefits of Chord, such as accelerating the lookup, and developed an energy efficient routing protocol for Wireless Sensor Networks, called CHEARP: Chord-based Hierarchical Energy-Aware Routing Protocol for Wireless Sensor Networks.…”