International Journal of Control and Automation Vol. 11, No. 10 (2018), pp.31-44 http//dx.doi.org/10.14257/ijca.2018.11.10.04 ISSN: 2005-4297 IJCA Copyright © 2018 SERSC Australia Student t-test for Scalable Topology for TSCH based IIoT Networks * Seema Kharb 1* and Anita Singhrova 2 1,2 Computer Science & Engineering Department, DCRUST, Murthal, India 1* seema016.phd@gmail.com, 2 nidhianita@gmail.com Abstract The Industrial Internet of Thing (IIoT) is a logical extension of automation and connectivity, that has evolved as an integral part of an industrial domain known as machine to machine communication. The IIoT networks have stringent requirements of traffic differentiation, reliability, low power consumption, scalability and timeliness for its various applications. Time Slotted Channel Hopping (TSCH) is the technology that provides ultra- low power and reliable communication to IIoT networks. Since, IIoT involves large number of devices, thus scalability of the network is the key concern nowadays. Accordingly, a scalable topology is to be selected for TSCH based IIoT networks. This work identifies the major topologies being used in industrial networks. Based on their limitations and key features, a two-tier topology is proposed for handling traffic differentiation and scalability in TSCH environment. The simulations for linear, star, mesh and proposed two-tier is carried out using 6TiSCH simulator. The proposed two-tier showed better results for large number of connected nodes and transmission cells, i.e., dense networks. The results were further verified by the method of hypothesis testing. Keywords: Student’s t-test, 6TiSCH Simulator, transmission cells, number of connected nodes 1. Introduction Industrial Internet of Things (IIoT) is a system that connects machines, controllers, sensors etc., to provide a foundation for smart homes, smart cities, smart manufacturing and smart factories. These smart factories will incorporate intelligent monitoring in traditional factories and make them adaptable and efficient. For this purpose, several standards based on IEEE 802.15.4 like WirelessHart, ISA100.11a, Zigbee etc., have been designed. The unsuitability of IEEE 802.15.4 for Industrial networks has led to the foundation of IEEE 802.15.4e standard in 2012 [1], with various MAC layer amendments .Time Slotted Channel Hopping (TSCH) is one of those MAC layer amendments that supports application domains of process automation, control and equipment monitoring. Moreover, through multichannel communication and channel hopping it is able to provide low power and reliable communication. Therefore, it becomes a candidate solution for Industrial Internet of Things (IIoT). An efficient IIoT system must be able to meet the stringent requirements of power consumption, reliability, latency, service differentiation, interoperability, scalability and efficient selection of network topology [2][5]. Network topology has a significant impact on various network performance metrics like energy consumption, latency, QoS etc. Further, network topology plays an important role in designing an efficient scalable network. The details for some of the existing projects in IWSN and the topologies used in them has been discussed in Table 1. After the detailed review, it has been observed that Received (May 6, 2018), Review Result (July 24, 2018), Accepted (August 8, 2018) * Corresponding Author