Introducing a simulation tool for WirelessHART networks

WirelessHART is an emerging wireless communication standard that is targeted at the real-time process control industry.An example application of wireless communication in an industrial process control plant is the location of field engineers. The capability to locate personnel is a safety critical issue in process control plants because of high risks posed by toxic chemicals and other hazards. This paper presents the design, implementation and evaluation of a location-aware application built upon WirelessHART. The aim of this application is to locate a mobile device (and thus the person carrying the device) via the deployed WirelessHART network. The application is a software-based - no device modifications are required. Consequently, it is applicable to any WirelessHART network. In this application, both the mobile device (a handheld device or a badge carried by a worker) and field devices (attached to the plant process) periodically send health reports of their neighbors to the network manager. The network manager analyzes these reports and discards the untrustworthy pairs through comparison. Next, the network manager feeds the average received signal indications to a well-trained radio propagation model to derive the location. To evaluation our solution, several preliminary experiments are carried out and the results are very promising, with a median error less than 4 meters, which is good enough for the industrial requirement. To the best of our knowledge, this is the first attempt to develop location-aware application in WirelessHART networks.

Current wireless technologies for industrial applications, such as WirelessHART and ISA100.11a, use a centralized management approach in which a central network manager handles the requirements of the static network. However, such a centralized approach has several drawbacks. For example, it cannot cope with dynamicity/disturbance in large-scale networks in a real-time manner while it also incurs a high communication overhead and latency for exchanging management traffic. In this thesis, we address the drawbacks of the centralized management approach utilized in WirelessHART and ISA100.11a for real-time industrial monitoring and control applications. More specifically, we propose new decentralized network management schemes to provide an end-to-end reliable and real-time communication for battery-powered and harvested-powered devices in a distributed manner. These schemes enable the network devices to join the network, schedule their communications, establish end-to-end connections by reserving communication resources to address real-time requirements, and cope with network dynamicity (e.g., node/edge failures) in a distributed manner. To evaluate wireless protocols in the domain of industrial monitoring and control, a reference point is needed. To that end, we developed a WirelessHART simulator in NS-2 as a reference point to evaluate other protocols. We validated the WirelessHART simulator with a WirelesHART deployment at an industrial plant. To the best of our knowledge, this is the first implementation that supports the WirelessHART network manager as well as the whole stack of the WirelessHART standard. To address the requirements of battery-powered I/O devices, we propose a distributed management scheme to address real-time and reliable communication requirements. This scheme considers the full mesh topology in which I/O devices are capable of participating in routing and distributed network management tasks, such as communication resources scheduling. We then propose a second distributed management scheme for hybrid networks to be used for real-time industrial wireless automation. This scheme addresses the requirements of energy constrained I/O devices. In this scheme, the I/O devices cannot participate in routing and distributed management tasks. The routers can dynamically reserve communication resources and manage the I/O devices in the local star sub-networks. We demonstrate that the proposed scheme achieves higher network management efficiency compared to the ISA100.11a standard, without compromising the latency and reliability requirements of industrial wireless networks. To better support and address the requirements of energy harvested I/O devices, we extend ISA100.11a. The proposed extension makes management more decentralized by delegating a part of the management responsibility to the routers in the network. It also allows the I/O devices to choose the best routers according to different metrics using local statistics and advertised routers’ ranks.

Focused interfaces for end-user network management

As SDN technology is becoming popular in the field of computer networks management, the need for evolvable SDN-based network management systems arises. SDN facilitates introducing abstractions to the network through programmability and control separation. In this paper, we propose an abstraction in the SDN management layer through adopting a concept of separation of network concerns. We present a management framework, termed NWManager, that provides an abstraction to the network administrator through policies based on network management functions, like behaviour analysis and monitoring, quality of service preservation and security. And based on network concerns as follows, application, communication, resources concern and common concern representing the area of intersection between basic concerns. NWManager provides various network management functions in one system. Our conducted network simulation scenario by mininet demonstrates that this abstraction and separation of concerns in management layer facilitates and enhances the management of the network. As well, it extends the network control parameters provided to the network administrator.

In this paper we describe a method to integrate WirelessHART networks in Distributed Control Systems (DCS) using PROFINET IO. By modeling the WirelessHART network in the Generic Station Description file, that describes a PROFINET IO device, the WirelessHART related configuration can be distributed from the central engineering stations. In this way, both process controller configuration and WirelessHART network configuration is engineered and maintained from a central location. Thus the end-user does not need any additional tool-specific training, as the existing tools are used to engineer the WirelessHART networks. We base the method of integration on the keywords simple deployment and maintenance, and flexible topology. A proof-of-concept implementation of the proposed method shows that it is possible to downloadWirelessHART configuration both to the WirelessHART network managers, as well as the WirelessHART sensors. By integrating WirelessHART in this way, maintenance is greatly simplified as the actual configuration will be downloaded automatically by the DCS when faulty field devices are replaced.

Cyber-physical systems are realized as those systems where the computation, communication and physical processes interact with each other (e.g., robotic systems, automotives, etc). A large class of cyber-physical systems are associated with strict timeliness requirements. They are known as ‘real-time systems’ (e.g., smart grids, avionics, etc). Industrial control systems (ICS) are real-time systems that consist of several closed-loop controls. The main components of a control loop are — a physical plant, sensors, actuators and a controller. The sensors transmit the measurement data to the controller that generates appropriate control signals to actuate the physical plant. Large-scale wireless sensor actuator networks form the main communication framework among the network devices in ICS. Most of the communications between each of these devices are periodic real-time flows with hard deadlines. To ensure reliability, the communication in these systems are time-division multiple access (TDMA) based. Dedicated network resources (time-slots and frequencies) are allocated to these devices in advance and the communication schedule is pre-computed to satisfy the hard deadlines of the real-time flows. The same schedule is repeated over time which makes the schedule predictable in nature. However, a malicious attacker can exploit this predictable time-slots in the schedules to launch timing attacks. Since these applications are time-critical, timing attacks can completely undermine the system performance leading the system to an unsafe state. Schedule randomization is a popular defense mechanism to mitigate timing attacks. Although a few works exist in the literature that use schedule randomization as a countermeasure against timing attacks in real-time uniprocessor systems, none of them are applicable for real-time wireless networks. Schedule randomization as a countermeasure against timing attacks in real-time wireless networks remained largely unexplored. With this objective in focus, this thesis addresses some schedule randomization techniques to mitigate timing attacks in real-time wireless networks. Among the existing wireless network protocols that are in use, the WirelessHART is the most suitable and widely adopted protocol in ICS. A WirelessHART protocol supports centralized architecture, TDMA based communication, multiple channels, etc. All of these characteristics of a WirelessHART network facilitate reliable and predictable communication with real-time flow guarantees in ICS. However, the predictable communication exposes the system to timing attacks, such as selective jamming attacks. Selective jamming attacks are stealthy attacks, however, it can lead the system to an unstable state and can disrupt the safety of the system. As a countermeasure against such attack in WirelessHART network, we propose a centralized schedule randomization technique that randomizes the time-slots and channels in the schedule over every hyperperiod (least common multiple of the periods of the real-time flows) without violating the hard deadlines of the real-time flows, while still satisfying the feasibility constraints of a schedule in a WirelessHART network. The centralized technique generates the schedules offline and distributes the schedules online, hence, cannot support any change in topology in the network. Further, this technique has energy overheads in distributing the schedules to all the network devices at runtime. Hence, we propose a distributed online schedule randomization technique that can generate random feasible schedules at runtime in each network device without affecting the closed-loop control stability. To increase the extent of randomization of time-slots in the schedules, this online distributed technique adopts a period adaptation strategy that can adjust the transmission periods of the real-time flows at runtime depending on the stability of the closed-loop controls. To support an ever-growing number of devices and dense connectivity, the fifth generation (5G) cellular networks is expected to serve as the main communication standard in the future wireless sensor networks. Among the different service categories supported by 5G, the ultra-reliable low-latency communication (URLLC) is mostly suitable for time-critical applications such as the ICS. The communication in 5G is organized into slots over multiple frequencies. To satisfy the hard deadlines of the URLLC flows in ICS, a part of the resources (slots and frequencies) in 5G are reserved for URLLC traffic and the same schedule is repeated over time. The repetition of the same schedule over time makes the slots in the schedules predictable. This, in turn, makes the 5G networks vulnerable to timing attacks. However, the proposed schedule randomization techniques for WirelessHART networks are not applicable for dynamic networks like 5G where the number of flows and the amount of available network resources for URLLC flows vary at runtime. Moreover, the feasibility of the real-time flows need to be guaranteed at runtime. Hence, we propose an online schedule randomization technique that randomizes the slots and the frequencies of the periodic URLLC flows while guaranteeing the feasibility of the flows at runtime.

While the networks of different Telecommunications Administrations forming a global network are interconnected, their Network Management Systems (NMSs) are isolated from each other. As a result, various network management functions (e.g., configuration, fault management) necessary for managing the network resources common to the administrations require extensive manual coordination and exchange of information using telephone and facsimile. In this paper, we present a standards based interoperable interface between network management systems belonging to different administrations. The interface is based on Telecommunications Management Network (TMN) architecture and standards. It is intended to automate and standardize information exchanged between the administrations so that network maintenance and provisioning activities could be done with minimal human involvement at the far-end administration. The interface provides significant benefits in improving the quality and the cycle time of provisioning and maintenance, implementing proactive maintenance, and greater awareness of the end-to-end performance of the managed resources.

Network computing is changing rapidly these days. The mobile agent technology invented to overcome the complexity resulting due to the increasing size of network components rises new network management schemes. Many prototype applications providing mobile agent capability have been proposed for being used in network management. E-commerce and information retrieval are some of them. The motive behind the agent mobility is that, it addresses some limitations faced by traditional centralized client-server architecture, which are mainly, minimizing bandwidth consumption, supporting network load balancing, enhancing scalability as well as flexibility, increase fault tolerance and solve problems caused by unreliable network connections. However, despite its benefits, mobile agent systems still pose security threats. In this paper we propose a mobile agent architecture that supports flexible and reliable interaction of autonomous components in a distributive network environment. We present a management scheme in a hierarchical level that provides to a user with a reliable and flexible global access to Internet/network information services. We further describe a protection mechanism to both agents and their hosting sites of execution called agent servers

Many cognitive radio (CR) networks adopt the collaborative sensing strategy that combines the sensing results of multiple CR stations, for getting the better primary user (PU) detection performance. In the practical CR networks with collaborative sensing, since a station reports the sensing result to a fusion center through a message, the reporting overhead is not negligible. In this paper, we design a sensing management scheme for CR networks, while taking this reporting overhead into account. First, we formulate an optimization problem that aims at finding the optimal number of sensing stations which collaborate to maximize the PU detection probability for given sensing/reporting time. Then, we propose a heuristic scheme to efficiently select the collaborative sensing stations, without a priori information for the locations of stations. Furthermore, we determine the optimal sensing interval for minimizing the PU detection delay while maintaining the CR channel utilization to a target value, by using a Markov analysis. The simulation results show that the proposed sensing management scheme significantly improves the PU detection performance.

Trust management is fundamental to identify malicious, selfish, and compromised nodes which have been authenticated. Many trust management mechanisms are proposed to provide effective security solution for wire and wireless networks, even some of them have become one of the most known in this field. But in fact, trust management in wireless sensor networks still remains a challenging field. Traditional trust models developed for wireless sensor networks are not well suited for sensor networks because the trust evaluation process isn’t related to certain application. In this paper, we propose a self-adaptive trust management scheme, which can adaptively adjust the trust evaluation process to cope with application requirement changes of trust management. The simulation results show that our scheme has less rate of inauthentic downloads of nodes, energy consumption and message overheads as compared to the current state-of-the-art trust management schemes, and it is more suitable for large-scale sensor networks.

Key management for wireless sensor networks meets new challenges due to its special properties. However, key distribution is a key problem for wireless sensor networks key management. In this paper, literature researches on WSN key distributions are reviewed at first, and the popular key pre-distribution schemes and protocols are analyzed. Then, a new key management scheme based on the novel cryptographic technique named bilinear pairing is proposed, as well as its security and performance are all discussed.

This paper presents an architecture of a managed object view interface (MOVI) for distributed network management system managing communication networks for distributed systems, specially for overlapping domain management. The hierarchical domain approach has been adopted for efficient management. We have introduced the MOVI to provide a means to construct a management platform for distributed networked systems. The integration of different networks which have different network management schemes can be achieved with this hierarchical architecture and MOVI. To support the overlapping managed object among several management domains, the MOVI uses the group communication facility. The system has been designed and implemented in the CNUNet (Changwon National University Network) environment, which is a distributed experimental campus network composed of several minicomputers and several hundreds of workstations. The components are interconnected with ring-type backbone network (FDDI), several bus-type networks (Ethernet) and wireless LAN.

Two main advantages of incorporating satellites into future computer networks are considered to be the large communication bandwidth of a satellite channel and the capability of using broadcast communications to nodes distributed over a very large geographical area. The inherent problem with satellites is that a large propagational delay is required by packet transmissions. A hierarchical VLAN model called an information flow model is presented. The model attempts to take advantage of the pluses of using satellites while minimizing the negative aspects by incorporating innovative network organization and management schemes. A description is given of the model, the network organization and its functional network management scheme, the simulation setup, implementation issues, parameters of the simulation model, and validation and verification. The design of experiments using the simulation model and the simulation results are also presented and analyzed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

With the development of smart grid and Internet of Things technology, the level of substation intellectualization is getting higher and higher. In order to monitor the substation equipment in real time and obtain the information of equipment operation status, a large number of monitoring sensors are installed on the equipment. Because of the complex internal environment and many dangerous factors in the substation, monitoring nodes usually use wireless communication and rely on their own batteries for power supply. Because the replacement of batteries is not convenient, node power consumption is very important for its lifetime. Traditional monitoring devices install SIM card, but according to this way, the power consumption of the device is large, so it needs to be connected separately to supply power for the device. At present, the main method is to form a network in the station, and the nodes gather information uniformly in the station. Because of the different transmission distance, each node sends information directly, which leads to its own battery consumption too fast, and the generation time of nodes is relatively short. In order to prolong working time and improve energy efficiency, a low-power sensor network technology based on node energy for transformer equipment is proposed in this paper. The energy consumption of each node is balanced by considering the node energy in the process of information transmission, thus prolonging the node lifetime and monitoring the network lifetime.

In this paper we describe a distributed and dynamic architecture for network management of a heterogeneous distributed system which we have implemented in order to perform network management of our local distributed system. The architecture is highly generic in nature and can be extended to a large heterogeneous network. The architecture is distributed in nature as it provides for multiple managers acting simultaneously. It is rendered dynamic by the utilization of mobile agents for the implementation of network management functionalities. The network managers in our architecture utilize client-server technology and/or mobile agent technology as and when required depending on the functionality implemented and their location. In this context we have implemented a Mobile Network Manager (MNM) which is a location independent network manager. Mobile agents are furnished by MAGENTA (Mobile AGENT environment for distributed Applications) which we have implemented for this purpose.