An Autonomous Distributed Control Method for Link Failure Based on Tie-Set Graph Theory

Ethernet networks using rapid spanning tree protocol (RSTP) to ensure a loop-free topology and provide redundant links as backup paths in case an active link has failed. However, when a failure occurs, RSTP requires a significant amount of reconfiguration time in order to find an alternative path. RSTP is also limited by the number of nodes in a ring network, and its performance degrades when the number of nodes increases. In this paper, we introduce a new approach, called loop prevention and load balancing (LPLB), which can be applied to Ethernet ring networks. If failure occurs, LPLB only requires a very short amount of time to switch to an alternative path and in most cases; LPLB needs zero recovery time for that switching. In addition, under most situations, no data frames are lost when a node switches to an alternative path. Unlike RSTP and the media redundancy protocol (MRP), LPLB also provides load balancing among network links that in turn improves the network performance and reduces the probability of bottleneck occurrence.

The Industrial Internet of things (IIoT), the implementation of IoT in the industrial sector, requires a deterministic, real-time, and low-latency communication response for its time-critical applications. A delayed response in such applications could be life-threatening or result in significant losses for manufacturing plants. Although several measures in the likes of predictive maintenance are being put in place to prevent errors and guarantee high network availability, unforeseen failures of physical components are almost inevitable. Our research contribution is to design an efficient communication prototype, entirely based on internet protocol (IP) that combines state-of-the-art communication computing technologies principles to deliver a more stable industrial communication network. We use time-sensitive networking (TSN) and edge computing to increase the determinism of IIoT networks, and we reduce latency with zero-loss redundancy protocols that ensure the sustainability of IIoT networks with smooth recovery in case of unplanned outages. Combining these technologies altogether brings more effectiveness to communication networks than implementing standalone systems. Our study results develop two experimental IP-based industrial network communication prototypes in an intra-domain transmission scenario: the first one is based on the parallel zero-loss redundancy protocol (PRP) and the second one using the high-availability seamless zero-loss redundancy protocol (HSR). We also highlight the benefits of utilizing our communication prototypes to build robust industrial IP communication networks with high network availability and low latency as opposed to conventional communication networks running on seldom redundancy protocols such as Media Redundancy Protocol (MRP) or Rapid Spanning Tree Protocol (RSTP) with single-point of failure and delayed recovery time. While our two network communication prototypes—HSR and PRP—offer zero-loss recovery time in case of a single network failure, our PRP communication prototype goes a step further by providing an effective redundancy scheme against multiple link failures.

The International Electrotechnical Commission (IEC) 61850 standard describes the communication inside the substation automation system (SAS) setting the base for new interoperating devices that share information using the Ethernet network infrastructure. More recently, the request of time synchronization among SAS components for the timestamping of critical events or synchrophasor measurement has generated a very high interest in the IEC 61850 working group for distributed synchronization protocols like IEEE 1588. This paper analyzes the current situation, matching different implementations of the IEEE 1588, and their respective accuracy, with the requirements of typical SAS applications: from the millisecond synchronization accuracy required by fault recorder application to the microsecond required by the sampled values (SV). The main focus of this paper is on the integration of IEEE 1588 with real already existing systems, and the goal is the performance comparison of different architectures. For these reasons, experimental tests have been carried out using a real SAS network infrastructure [redundant gigabit optical fiber Ethernet network managed using rapid spanning tree protocol (RSTP)]. The results show that, under ideal conditions, the IEEE 1588 protocol can achieve synchronization accuracy slightly worse (80 ns) than legacy IRIG-B systems (15 ns). However, IEEE 1588 makes possible a great cabling reduction and a simplified maintenance when synchronization is directly transferred on the SAS system bus. On the other hand, experiments highlight that nodes connected through a legacy RSTP infrastructure, which does not support IEEE 1588 messages, can lose the time synchronization in the case of network traffic or reconfiguration of the network. Therefore, the integration of IEEE 1588 over existing IEC 61850 station bus is basically a tradeoff between installation costs and performance since it requires the replacement of already installed Ethernet infrastructure. In the last part, this paper analyses the challenges for the next SAS generation that has to combine on the same plants the high accuracy IEEE 1588 implementation with high-availability protocols based on IEC 62439. Since the lifetime of an SAS is more than ten years and the adoption of these technologies takes several years, some solutions that introduce synchronization and high-availability protocols guaranteeing compatibility with existing technologies have been analyzed, too. For instance, an adaptation block that (when attached to a high-availability network) reconstructs the interface signals (e.g., synchronization signals) required by traditional bay has been proposed.

The communications standard IEC 61850-5 identifies fast messages that perform high-speed automation, protection, and interlocking to meet or exceed a transmission time of 3 milliseconds as Type 1A, Performance Class P2/P3. Modern microprocessor-based devices and Ethernet networks routinely meet this requirement when everything is working as expected. One of the most important acceptance criteria (and perhaps least understood) is the maximum transmission time when unexpected things do happen and messages are delayed. Because not all paths in an Ethernet network perform the same, this paper introduces path performance classifications that illustrate the minimum and maximum transfer times between two devices. The telecommunications performance standard IEC 60834-1 is commonly used to evaluate point-to-point high-speed automation and interlocking. It describes the overall operating time between the instant of the change of state at the command input on the source device and the instant of the change of state at the command output on the destination device. This includes propagation time and any additional delays. IEC 60834-1 further defines transmission dependability as the ability to receive each command message within the fixed actual transmission time defined by the application, in this case 3 milliseconds. IEC 61850-5 specifically states that testing and verification of the complete transfer time must be performed during site acceptance testing using the physical devices and network equipment. Methods to test and validate message transmission during normal Ethernet packet delivery as well as during path failure are introduced in this paper based on both Rapid Spanning Tree Protocol (RSTP) and Parallel Redundancy Protocol (PRP).

If assumed that each Ethernet standard (IEEE 802.3) node has more than one port connected to the network and the node duplicates each sent frame, then an active or a seamless redundancy will be established because the destination node will receive at least two frame copies with zero recovery time. In this paper, we present a novel method for eliminating the duplicated frames in any Ethernet network type. This will ensure that the destination node will only consume one frame copy from each sent frame and eliminate the other copies. The proposed method will set a counter on each receiving port in the destination node. The destination node will consume the copy that arrives through the fastest path, or in other words, through the port that has the fastest counter value. The proposed method does not need to disable ports as required by rapid spanning tree protocol (RSTP) or the media redundancy protocol (MRP), to avoid looping issues; instead, it activates all ports to provide a type of better traffic distribution among the network links.

The Spanning Tree Protocol (STP), standardized in IEEE 802.1D, has served as the foundational loop-prevention mechanism in bridged Ethernet networks for over three decades. Despite its widespread adoption, STP exhibits significant limitations with respect to convergence time, bandwidth utilization, and scalability that are increasingly incompatible with the demands of modern enterprise and data center networks. This paper presents a structured comparative analysis of five major Layer 2 protocols in the STP lineage: STP (IEEE 802.1D), Rapid Spanning Tree Protocol (RSTP, IEEE 802.1w), Multiple Spanning Tree Protocol (MSTP, IEEE 802.1s), Shortest Path Bridging (SPB, IEEE 802.1aq), and Transparent Interconnection of Lots of Links (TRILL, RFC 6325). The analysis is conducted along four primary dimensions: convergence time, scalability, operational complexity, and security considerations. Drawing exclusively on peer-reviewed literature, IETF/IEEE standards, and published operational benchmarks, the paper concludes with a structured evaluation of the relevance of these protocols in Software-Defined Networking (SDN) environments and modern Ethernet fabric architectures, proposing a conceptual decision framework for protocol selection.

Ethernet's high performance, low cost, and ubiquity have made it the dominant networking technology for many application domains. Unfortunately, its distributed forwarding topology computation protocol-the Rapid Spanning Tree Pro-tocol (RSTP)-is known to suffer from a classic count-to-infinity problem. However, the cause and implications of this problem are neither documented nor understood. This paper has three main contributions. First, we identify the exact conditions under which the count-to-infinity problem manifests itself, and we characterize its effect on forwarding topology convergence. Second, we have discovered that a forwarding loop can form during count to infinity, and we provide a detailed explanation. Third, we propose a simple and effective solution called RSTP with Epochs. This solution guarantees that the forwarding topology converges in at most one round-trip time across the network and eliminates the possibility of a count-to-infinity induced forwarding loop.

A computer network can be defined as many computing devices connected via a communication medium like the internet. Computer network development has proposed how humans and devices communicate today. These networks have improved, facilitated, and made conventional forms of communication easier. However, it has also led to uptick in-network threats and assaults. In 2022, the global market for information technology is expected to reach $170.4 billion. However, in contrast, 95% of cyber security threats globally are caused by human action. These networks may be utilized in several control systems, such as home-automation, chemical and physical assault detection, intrusion detection, and environmental monitoring. The proposed literature review presents a wide range of information on Wireless Social Networks (WSNs) and Internet of Things (IoT) frameworks. The aim is first to be aware of the existing issues (issues with traditional methods) and network attacks on WSN and IoT systems and how to defend them. The second is to review the novel work in the domain and find its limitations. The goal is to identify the area’s primary gray field or current research divide to enable others to address the range. Finally, we concluded that configuration. Message Rapid Spanning Tree Protocol (RSTP) messages have higher efficiency in network performance degradation than alternative Bridge Data Unit Protocol (BPDU) forms. The research divides our future research into solutions and newly developed techniques that can assist in completing the lacking component. In this research, we have selected articles from 2015 to 2021 to provide users with a comprehensive literature overview.

The authors develop graph-theoretical techniques using automorphisms to solve the problem of reconfiguring embedded task graphs in faulty hypercubes. Four cases are considered: single node or link failure, small number ( or=5) of random node failures. For single node (link) failure, any arbitrary task graphs embedded in a hypercube can be remapped to another instance of that graph by simple bit-flip operations. It takes at most O(n) such operations in an n-dimensional hypercube. For a small number of faults ( >

Along the coming years, an important increase of the energy consumption in the world is expected, what will lead the energy sector to deal with several challenges such us availability of delivering the demanded energy, increase of the emissions and greenhouse effect. Energy Management Systems are being integrated with domestic and residential applications, which optimize the home energy consumption. The Local Energy Management Unit is presented in this paper that allows an optimized power demand to the Grid. It utilizes different types of communication (by using TCP and X10 protocols) with the aim of obtaining an efficient energy management and allowing a lower power consumption, which lets the user to decrease the cost of the electric invoice. A prototype has been built that shows energy management results. The power demanded from the Grid is kept constant regardless of the house power consumption.DOI: http://dx.doi.org/10.5755/j01.eee.19.7.5164

PurposeDuring the COVID-19 pandemic, Local Educational Management Units (UGELs), the key government stakeholders in the provision of education services in Peru, implemented responsive interventions. This paper analyses the relationship between UGEL organisational resilience and their responses during this period.Design/methodology/approachA survey was conducted to measure UGEL management practices, with 251 valid responses from directors and managers. Based on organisational resilience theory, 67 questions were grouped into 13 factors and 3 components: (1) leadership and organisational culture, (2) preparation for change, and (3) networks building on the Organisational Resilience Index (ORI). These factors correlated with the number of interventions and the impact of those interventions implemented by UGELs.FindingsThe findings indicated that of all ORI components, leadership and organisational culture ranked the highest. Moreover, the ORI is positively associated with the number of interventions and the perceived impact produced by those interventions. Interestingly, it was found that when the gender variable is included in the correlation between the ORI and the number of interventions, women leading UGELs display a higher number of interventions than their male counterparts; and the coefficient increases even more when women lead a UGEL in a more challenging context (i.e., when the UGEL is located in a low-income area and operates under scarce resources).Originality/valueThis is the first study in Peru which analyses organisational resilience in the education sector, specifically about UGELs during the COVID-19 pandemic. It may help set priorities for institutional strengthening initiatives aimed at improving organisational resilience, which is particularly important in such uncertain and changing contexts.

Approximate concept and graph theory are developed and applied to solve the integrated optimization problem of engineering structure containing both beam and plate discrete variables. Firstly, both structural responses and explicit requirements for process manufacturing are considered as constraints, which makes an optimization system based on the two-level multi-point approximation method more engineering oriented. Secondly, a practical evaluation method of topology rationality is proposed based on graph theory in order to avoid invalid structural analysis and improve optimization efficiency. The finite element model corresponding to the binary point-line relation in graph theory and judgements of force nodes, lump masses, structural integrity, etc. are unified. An engineering example shows that the two-level multi-point approximation method is still efficient in solving topology optimization problems with participating plates and beams, and the proposed topological rationality evaluation method can effectively eliminate about 15% of unreasonable configurations.

Modelling spatial distributions of alpine vegetation: A graph theory approach to delineate ecologically-consistent species assemblages

In this research, a smart lighting system based on a new autonomous distributed control method was developed to control lighting using illuminance sensors. By using infrared ray communication, one illuminance sensor sends a luminance control directive to several lighting fixtures located nearby. The luminance is made to change randomly within a fixed range to optimize the illuminance using the stochastic hill climbing method. The result of operational experiments using illuminance sensors that were preset to the target illuminance showed that the brightness at specified locations approached the target illuminance that the illuminance sensors were set to. The electrical power consumed by the lighting system was also minimized. Moreover, in comparison with lighting driven autonomous distributed controls of smart lighting systems, better results were obtained, indicating that the method is an effective new distributed control method.

An efficient critical protection scheme for intra-domain routing using link characteristics