Volume 12, Number 2

Performance Evaluation of Modbus TCP in Normal Operation and Under A
Distributed Denial of Service Attack

  Authors

Eric Gamess¹, Brody Smith¹ and Guillermo Francia III², ¹Jacksonville State University, USA and ²University of West Florida, USA

  Abstract

Modbus is the de facto standard communication protocol for the industrial world. It was initially designed to be used in serial communications (Modbus RTU/ASCII). However, not long ago, it was adapted to TCP due to the increasing popularity of the TCP/IP stack. Since it was originally designed for controlled serial lines, Modbus does not have any security features. In this paper, we wrote several benchmarks to evaluate the performance of networking devices that run Modbus TCP. Parameters reported by our benchmarks include: (1) response time for Modbus requests, (2) maximum number of requests successfully handled by Modbus devices in a specific amount of time, and (3) monitoring of Modbus devices when suffering a Distributed Denial of Service attack. Due to the growing adoption of IoT technologies, we also selected two widely known and inexpensive development boards (ESP8266 and Raspberry Pi 3 B+/OpenPLC) to realize a performance evaluation of Modbus TCP.

  Keywords

Modbus, Internet of Things, Programmable Logic Controllers, Security, DDoS, Network Evaluation, Benchmark.