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SDN has the ability to transform network design by providing increased versatility and effective regulation. Its programmable centralized controller gives network administration employees more authority, allowing for more seamless supervision. However, centralization makes it vulnerable to a variety of attack vectors, with distributed denial of service (DDoS) attacks posing a serious concern. Feature selection-based Machine Learning (ML) techniques are more effective than traditional signature-based Intrusion Detection Systems (IDS) at identifying new threats in the context of defending against distributed denial of service (DDoS) attacks. In this study, NGBoost is compared with four additional machine learning (ML) algorithms: convolutional neural network (CNN), Stochastic Gradient Descent (SGD), Decision Tree, and Random Forest, in order to assess the effectiveness of DDoS detection on the CICDDoS2019 dataset. It focuses on important measures such as F1 score, recall, accuracy, and precision. We have examined NeTBIOS, a layer-7 attack, and SYN, a layer-4 attack, in our paper. Our investigation shows that Natural Gradient Boosting and Convolutional Neural Networks, in particular, show promise with tabular data categorization. In conclusion, we go through specific study results on protecting against attacks using DDoS. These experimental findings offer a framework for making decisions.

Recent advancements in AI have significantly propelled machine learning (ML) as a cornerstone of modern technological infrastructure, especially in enhancing machine-to-machine (M2M) communication. This necessitates the development of custom, advanced passive optical network (PON) devices tailored to sophisticated functionalities, heralding a shift towards decentralized data processing that aligns with global data protection and privacy standards. This paper introduces a novel software-defined architecture for TWDM-PON, designed to support Federated Learning (FL) traffic in a peer-to-peer (P2P) manner. Our proposed architecture integrates an advanced P2P-FL-OLT with an enhanced P2P-FL-DBA and P2P-FL-ONU with cache storage and a dedicated P2P transceiver, optimizing network resources and enhancing performance. Extensive simulations demonstrated that this architecture effectively manages increased P2PFL traffic, substantially improving system performance metrics such as throughput, packet delay, jitter, and packet loss ratio. The results affirm that our design not only meets but exceeds Quality of Service (QoS) requirements, making it a viable solution for future fiber optic networks facilitating distributed M2M machine learning applications.

An alternative networking approach called Software Defined Networking (SDN) enables dynamic, programmatically efficient network construction, hence enhancing network performance. It splits a traditional network into a centralized control plane and a configurable data plane. Because the core component overseeing every data plane action is the controller in the control plane, which may contain one or more controllers and is thought of as the brains of the SDN network, controller functionality and performance are crucial to achieve optimal performances. There is much controller research available in the existing literature. Nevertheless, no qualitative comparison study of OpenFlow-enabled distributed but logically centralized controllers exists. This paper includes a quantitative investigation of the performance of several distributed but logically centralized SDN controllers in custom network scenarios using Mininet, as well as a thorough qualitative comparison of them. More precisely, we give a qualitative evaluation of their attributes and classify and categorize 13 distributed but logically centralized SDN controllers according to their capabilities. Additionally, we offer a comprehensive SDN emulation tool, called Mininet-based SDN controller performance assessment, in this study. Using six performance metrics—bandwidth, round-trip time, delay, jitter, packet loss, and throughput—this work also assesses five distributed but logically centralized controllers within two custom network scenarios (uniform and non-uniform host distribution). Our analysis reveals that the Ryu controller outperforms the OpenDayLight controller in terms of latency, packet loss, and round-trip time, while the OpenDayLight controller performs well in terms of throughput, bandwidth, and jitter. Throughout the entire experiment, the HyperFlow and ONOS controllers performed worst in all performance metrics. Finally, we discuss detailed research findings on performance. These experimental results provide decision-making guidelines when selecting a controller.

Optical networks have undergone a remarkable transformation with the adoption of Artificial Intelligence (AI) techniques such as Machine Learning (ML) and Deep Learning (DL). The Next Generation (NG)-EPON is one such technology that is essential for supporting high-bandwidth applications like 4K video streaming, ultra-high-definition (UHD) CCTV, and other emerging video-type applications that have strict Quality-of-Service (QoS) requirements. In this paper, we present a ground-breaking Temporal Dynamic Wavelength Bandwidth Allocation (T-DWBA) mechanism based on the Long-Short-Term-Memory (LSTM) architecture. The T-DWBA uses past experiences to learn data as knowledge and predict time series with time lags of unknown size. Our proposed mechanism reduces upstream control message overheads, eliminates idle periods, and significantly improves bandwidth utilization, ensuring superior QoS specifically for video-type applications. The simulation results show that the T-DWBA significantly enhances system performance, reducing packet delay, and jitter, and improving bandwidth utilization. The use of AI techniques like ML and DL coupled with the recent advancements in SDN-Enabled Broadband Access (SEBA), hardware/software, and cloud technologies provide the perfect platform for deploying our proposed T-DWBA mechanism. Overall, our research proposes a promising solution for boosting EPON performance, revolutionizing optical networks, and providing seamless access to high-quality video streaming for a next-generation audience.

Over the past decade, network operators worldwide have regarded passive optical networks (PONs) as a successful access network system and the preferred technology for fiber-to-the-home/building/curb/distribution-point (FTTx) architecture. However, implementing the state-of-the-art PONs requires a high initial capital expenditure (CapEx) to deploy fiber in the field and acquires the necessary active devices. Thus, new architectures need to be developed to share the physical architecture and enable the multi-tenancy capability in a flexible way to satisfy different requirements from the operators and users. This research proposes to integrate the next-generation TWDM-PON with software-defined network (SDN) and the network function virtualization (NFV) to provide highly enhanced form of virtual unbundling of broadband access networks, enabling cost sharing and the dynamics of a competitive landscape. The simulation results show that the proposed architecture and mechanism can provide better performance in multi-tenancy condition, while guaranteeing the quality-of-service requirements in terms of the mean packet delay, jitter, throughput, and packet loss ratio.

The purpose of this study is to increase the number of access users without having to install a new optical cable. With the proposed solution, the cost of installation work can be reduced and the number of users can be increased. Several parameters were observed to ensure that the modified network not only improved the scalability but also met the standard parameters. Among the parameters observed are the Q factor, bit error rate (BER), eye diagram and number of users. The study was continued using the spectrum conversion, slicing and duplication technique, where the signals would be duplicated in arrayed waveguide grating (AWG) and sliced using a demultiplexer WDM (WDM Demux). Simulations were performed using the latest-version Optisystem 18.0 software by setting the transmitter frequency value of 1491 nm, transmitter power of 0 dBm and loss of 0 dB. The result shows the total user access achieved is 196,608 users. Meanwhile, the common FTTH network is allowed 256 users only. The criterion is set based on the calculation of the Q factor, which is greater than 6, while the BER is less than 1 × 10−9. The Q factor for 196,608 users is 6.43617 and the BER is 4.52 × 10−11. The number of users is increased without compromising the quality of data offered to the customer. Our solution is the first reported to date.

File sharing is one of the most common uses in Peer-to-peer (P2P) networks and structured P2P systems, such as BitTorrent (BT), which may overcome the limitations of features such as improved scalability, efficiency, and deterministic data location. Recent research has attempted to reduce inter-ISP P2P traffic by including locality awareness into neighbor-selection strategies of popular P2P apps, which prioritize adjacent peers over distant peers when transferring data, reducing server bandwidth burden, and inter-ISP traffic expense. However, the locality awareness P2P exchanged, handled and coordinated by the network infrastructure to turn around traffic as nearest as possible to the end users was proposed for the passive optical network (PON) because of the large amount of bandwidth in only one single fiber. The PON offers many system architectures; in particular, the NG-PON2 with colorless ONUs, adopting time and wavelength division multiple access technology is often recognized as the best access network solution for simplifying network operation, lowering installation costs, and maintenance costs under control. Software-defined networking (SDN) has sparked interest in various fields as a viable research topic, promising better agility, improved automation, security, and lower capital and operating costs. Taking advantage of the SDN’s OpenFlow protocol in NG-PON2, centralized control renders more flexible control over the BT traffic (P2P intra-traffic) file sharing application provided by different ISPs. Finally, we evaluated our proposed scheme in real-time traffic share collected by Sandvine’s report on 2020 despite the Covid-19 pandemic for different geographic regions, for example; Global, APAC, EMEA, and AMERICA.

The IEEE 802.3ca Task Force group has recently approved the standardization of the next-generation Ethernet passive optical network (NG-EPON) to satisfy future bandwidth demands. NG-EPON architecture classifies the optical network unit (ONU) transmission to allow simultaneous Wavelength-Agile (WA-PON) transmission, which increases the network capacity (50 Gb/s) and flexibility. The recently launched 5G services and related functional standards, new capabilities, and quality of service (QoS) imposed on the optical transport network. The Peer-to-peer (P2P) based live streaming application is the most popular multimedia application in access networks, i.e., Facebook Live, YouTube Live, Twitch, and other streaming and video conferencing services are increasing, especially in global epidemics which requires a higher QoS. Hence, media-based applications require adequate infrastructure resources to meet customer demands such as high bandwidth, low latency, high quality audiovisual, live streaming, and services. Therefore, this paper proposes an SDN enhanced P2P virtual reality (VR) live video streaming application NG-EPON multicast architecture based on 5G-enabled Tactile Internet (TI) and aims to improve the QoS, QoE and provide flexible services to the end-users. Finally, we proposed an SDN-based TI-dynamic wavelength and bandwidth allocation (SD-TI-DWBA) mechanism. Simulation results show that our proposed architecture can improve the system performance and QoS metrics regarding packet delay, jitter, system throughput, and packet loss.

Historically, the optical access network (OAN) plays a crucial role of supporting emerging new services such as 4 k, 8 k multimedia streaming, telesurgery, augmented reality (AR), and virtual reality (VR) applications in the context of Tactile Internet (TI). In order to prevent losing connectivity to the current mobile network and Tactile Internet, the OAN must expand capacity and improve the quality of Services (QoS) mainly for the low latency of 1 ms. The optical network has adopted artificial intelligence (AI) technology, such as deep learning (DL), in order to classify and predict complex data. This trend mainly focuses on bandwidth prediction. The software-defined network (SDN) and cloud technologies provide all the essential capabilities for deploying deep learning to enhance the performance of next-generation ethernet passive optical networks (NG-EPONs). Therefore, in this paper, we propose a deep learning long-short-term-memory model-based predictive dynamic wavelength bandwidth allocation (DWBA) mechanism, termed LSTM-DWBA in NG-EPON. Future bandwidth for the end-user is predicted based on NG-EPON MPCP control messages exchanged between the OLT and ONUs and cycle times. This proposed LSTM-DWBA addresses the uplink control message overhead and QoS bottleneck of such networks. Finally, the extensive simulation results show the packet delay, jitter, packet drop, and utilization.

Fiber-to-the-home (FTTH) networks are seen as the most future-proof technology to offer increasing bandwidth to customers. By utilizing passive optical network (PON) technology, they provide flexibility and capability to carry higher bandwidths as compared to the legacy copper-based access network. Optical performance monitoring could potentially enable higher stability, reconfigurability, and flexibility in a self-managed optical network. This paper will describe the specific fiber impairments that affect the quality of service for fiber-to-the-home networks. The impairment needs to be monitored and restored. The proposed solution will utilize a photodiode and optical switch as the main components, can easily be integrated with the ONU through the optical interface, and will be referred to as ‘PROMO’. With this scheme, the protection and restoration mechanisms are archived through the detection and availability of the downstream signal from the OLT. The results show that the received power, BER values, and maximum Q factor are acceptable for both simulation and experimental conditions in the case of normal and protection conditions.

An Ethernet passive optical network (EPON) is an optical access network that allows a higher data rate with low power consumption. To improve energy savings for an EPON, the sleep and doze modes for the optical network units (ONUs) play a pivotal role. Many prediction schemes have been proposed to control these modes. To increase the prediction accuracy, this study proposes an energy-efficient approach that uses a support vector regression (SVR) model. A dynamic bandwidth allocation (DBA) scheme called SVR-DBA is designed to allocate bandwidth to ONUs more efficiently and fairly. To determine the effectiveness of the proposed scheme, simulations are performed. The simulation results show that the proposed scheme decreases energy consumption for ONUs by up to 47% and fulfills the quality-of-service (QoS) requirements in terms of delay, jitter, and packet loss.

Due to the rapid growth of the Internet of Things (IoT), applications such as the Augmented Reality (AR)/Virtual Reality (VR), higher resolution media stream, automatic vehicle driving, the smart environment and intelligent e-health applications, increasing demands for high data rates, high bandwidth, low latency, and the quality of services are increasing every day (QoS). The management of network resources for IoT service provisioning is a major issue in modern communication. A possible solution to this issue is the use of the integrated fiber-wireless (FiWi) access network. In addition, dynamic and efficient network configurations can be achieved through software-defined networking (SDN), an innovative and programmable networking architecture enabling machine learning (ML) to automate networks. This paper, we propose a machine learning supervised network traffic classification scheduling model in SDN enhanced-FiWi-IoT that can intelligently learn and guarantee traffic based on its QoS requirements (QoS-Mapping). We capture the different IoT and non-IoT device network traffic trace files based on the traffic flow and analyze the traffic traces to extract statistical attributes (port source and destination, IP address, etc.). We develop a robust IoT device classification process module framework, using these network-level attributes to classify IoT and non-IoT devices. We tested the proposed classification process module in 21 IoT/Non-IoT devices with different ML algorithms and the results showed that classification can achieve a Random Forest classifier with 99% accuracy as compared to other techniques.

Emerging research trends in smart healthcare, smart manufacturing, and Industrial Internet-of-Things (IIoT) applications are based on 5G services, which can achieve ultra-reliable and low-latency communication networks. In such fields of application, haptic applications have gained importance. The invention of 5G wireless communication networks and advances in Tactile Internet (TI) technology, which provides controlled communications through the transmission of touch and actuation in real-time, have been envisioned as promising enablers of TI services. This study introduces TI-based smart hospital healthcare applications to enhance the alignment of services provided to patients. The existing telesurgery system has high communication delay and overhead, which limit its applicability. To alleviate these problems, we analyze and provide insights into the communication architecture for 5G-enabled low-latency telesurgery in a smart hospital. We then propose a new TI-software-defined optical access networking (TI-SDOANs) framework in Next-Generation Passive Optical Network 2, which includes cloud-based human-to-machine steering servers and supports multiple cloud-based applications. We further propose the implementation of an effective TI-dynamic wavelength and bandwidth allocation (TI-DWBA) resource provisioning scheme that meets the quality of service requirements of TI services. Simulation results show that the proposed scheduling schemes can significantly improve the Quality of Service (QoS) performance in terms of the packet delay, jitter, throughput and packet drop.

Localization is an important research issue in Wireless Sensor Networks (WSNs). Though Global Positioning System (GPS) can be used to locate the position of the sensors, unfortunately it is limited to outdoor applications and is costly and power consuming. In order to find location of sensor nodes without help of GPS, collaboration among nodes is highly essential so that localization can be accomplished efficiently. In this paper, novel localization algorithms are proposed to find out possible location information of the normal nodes in a collaborative manner for an outdoor environment with help of few beacons and anchor nodes. In our localization scheme, at most three beacon nodes should be collaborated to find out the accurate location information of any normal node. Besides, analytical methods are designed to calculate and reduce the localization error using probability distribution function. Performance evaluation of our algorithm shows that there is a trade off betweendeployed number of beacon nodes and localization error, and average localization time of the network can be increased with increase in the number of normal nodes deployed over a region.

The K-coverage configuration that guarantees coverage of each location by at least K sensors is highly popular and is extensively used to monitor diversified applications in wireless sensor networks. Long network lifetime and high detection quality are the essentials of such K-covered sleep-scheduling algorithms. However, the existing sleep-scheduling algorithms either cause high cost or cannot preserve the detection quality effectively. In this paper, the Pre-Scheduling-based K-coverage Group Scheduling (PSKGS) and Self-Organized K-coverage Scheduling (SKS) algorithms are proposed to settle the problems in the existing sleep-scheduling algorithms. Simulation results show that our pre-scheduled-based KGS approach enhances the detection quality and network lifetime, whereas the self-organized-based SKS algorithm minimizes the computation and communication cost of the nodes and thereby is energy efficient. Besides, SKS outperforms PSKGS in terms of network lifetime and detection quality as it is self-organized.

The K-coverage configuration that guarantees coverage of each location by at least K sensors is highly popular and is extensively used to monitor diversified applications in wireless sensor networks. Long network lifetime and high detection quality are the essentials of such K-covered sleep-scheduling algorithms. However, the existing sleep-scheduling algorithms either cause high cost or cannot preserve the detection quality effectively. In this paper, the Pre-Scheduling-based K-coverage Group Scheduling (PSKGS) and Self-Organized K-coverage Scheduling (SKS) algorithms are proposed to settle the problems in the existing sleep-scheduling algorithms. Simulation results show that our pre-scheduled-based KGS approach enhances the detection quality and network lifetime, whereas the self-organized-based SKS algorithm minimizes the computation and communication cost of the nodes and thereby is energy efficient. Besides, SKS outperforms PSKGS in terms of network lifetime and detection quality as it is self-organized. [ABSTRACT FROM AUTHOR]

Conventional tag cloud systems can only present the frequency of tags and the connection of tags and tag clusters, but cannot properly express the strength of the relationships. In this paper we tackle this problem by improving the representation of tag clustering. We combine the advantages of conventional systems to create a multi-level interactive tag cloud system using clustering scheme. In our tag cloud system, tags are mapped onto a two-dimensional space. A force-directed algorithm is applied to make the tags move in 2D space. The tags will move until equilibrium is reached. As a result, the tags with high correlation are clustered in the close vicinity, and so are the tag clusters with high correlation. In addition, we let the users to interact with the tag cloud by zooming and panning for different perspectives and let user to select a tag than the tag will locate at the center of window and show the correlations of the user selected tag with other tags. We believe that our system can improve the user browsing experience, and can also be served as a great basis for social network analysis and other related research. [ABSTRACT FROM AUTHOR]

Localization is an important research issue inWireless Sensor Networks (WSNs). Though Global Positioning System (GPS) can be used to locate the position of the sensors, unfortunately it is limited to outdoor applications and is costly and power consuming. In order to find location of sensor nodes without help of GPS, collaboration among nodes is highly essential so that localization can be accomplished efficiently. In this paper, novel localization algorithms are proposed to find out possible location information of the normal nodes in a collaborative manner for an outdoor environment with help of few beacons and anchor nodes. In our localization scheme, at most three beacon nodes should be collaborated to find out the accurate location information of any normal node. Besides, analytical methods are designed to calculate and reduce the localization error using probability distribution function. Performance evaluation of our algorithm shows that there is a tradeoff between deployed number of beacon nodes and localization error, and average localization time of the network can be increased with increase in the number of normal nodes deployed over a region. [ABSTRACT FROM AUTHOR]

Ethernet Passive Optical Network (EPON) is proposed as a simple, cost-effective and scalable solution for bandwidth bottlenecks in access networks which can enhance the system performance because it transmits the aggregated high-speed traffic from hundreds of subscribers. Dynamic Bandwidth Allocation (DBA) mechanism has not yet been seriously considered for use in star-ring EPON architecture. In this paper, a distributed QoS-based dynamic bandwidth allocation (DQ-DBA) scheduling mechanism for the star-ring-based EPON architecture including optical line terminal (OLT), Sub-OLT and ONUs has been proposed to improve the system performance of traditional tree-based EPON architecture. In DQ-DBA, the highest-priority traffic of each ONU is directed to the OLT by the tree structure; moreover, the lower-priority traffic on each ONU is transmitted to the Sub-OLT by ring architecture. This approach can effectively resolve the idle period problem and reduce the overloading of OLT in conventional DBA mechanisms. Exhaustive simulation experiments are performed to compare the system performance between the tree and the star-ring architectures and validate the effectiveness of the proposed mechanism. Simulation results show that the proposed DQ-DBA mechanism in star-ring architecture can reduce packet delay and jitter for the high-priority traffic, thus ensuring the quality of service (QoS) regardless of subscriber numbers. [ABSTRACT FROM AUTHOR]

Abstract  This study proposes a novel cost-based fault-tolerant WDM-EPON (CFT-WDM-EPON) to provide overall protection. It only equips a backup feeder fiber to recover the system failure. Additionally, a prediction-based fair wavelength and bandwidth allocation (PFWBA) scheme is proposed to enhance the differentiated services for WDM-EPON based on dynamic wavelength allocation (DWA) and prediction-based fair excessive bandwidth reallocation (PFEBR) from our previous work. PFEBR involves an early-DBA mechanism, which improves prediction accuracy by delaying report messages of unstable traffic optical network units (ONUs), and assigns linear estimation credit to predict the arrival of traffic during waiting time. DWA can operate in coordination with an unstable degree list to allocate the available time of wavelength precisely. Simulation results show that the proposed PFWBA scheme outperforms WDM IPACT-ST and DWBA3 in terms of packet delay, jitter performance, throughput, wasted bandwidth, gain ratio of bandwidth, and packet loss. [ABSTRACT FROM AUTHOR]

Abstract  In the EPON, any failure of optical line terminal (OLT) or feeder fiber can halt the entire system. Many previous studies proposed dedicated protection architectures to protect the critical components, which results in high cost for deployment. To achieve high reliability and low-cost for deployment, this article proposes a novel fault-tolerant Multi-EPON system with cost-effective shared protection through Bridge ONUs. Under failures, the Bridge ONU controls the faulty EPON, plays the role of OLT and the transmission of faulty EPONs are restored by relaying to other interconnected adjacent EPONs. The minimum hop-count relay algorithm and the relay window mechanism are also proposed for the Multi-EPON system to efficiently help data relaying to the central office (CO). Furthermore, the one-wait dynamic bandwidth allocation enables the controller of affected Passive Optical Networks (PONs) to obtain more up-to-date buffer information from each ONU in order to enhance overall system performance. The simulation results show that the proposed Multi-EPON system can provide high system performance for different failure situations in terms of throughput, average delay, maximum delay, and expedited forwarding (EF) jitter, especially in high traffic loads. [ABSTRACT FROM AUTHOR]

Abstract  This article examines all-optical multicast routing for wavelength-routed optical networks with sparse Multicast Capable (MC) nodes in two phases. The first phase is MC node placement and use of a simple and straightforward Maximum Path Count First (MPCF) algorithm to obtain candidates for MC nodes. The second phase is multicast routing with MC-based schemes that minimizes the number of wavelength channels with minimum transmission delay as required by a given multicast session, in that a light-tree is first constructed to connect MC nodes in a multicast group by using two algorithms, namely, the Pre-computing Minimum Cost (PMC) tree algorithm and the Pre-computing Shortest Path (PSP) tree algorithm. System performance of the proposed MPCF MC node placement algorithm is compared with that of the Normalized Cuts (NC) MC node placement algorithm for both PMC and PSP multicast routing. Furthermore, simulation results compare PMC and PSP multicast routing based on MPCF and NC node placement with Re-route-to-Source (RTS), Re-route-to-Any (RTA), Member-First (MF), and Member-Only (MO) multicast routing based on a light forest for a given multicast session in terms of average number of wavelengths needed, average blocking probability, and mean maximum transmission delay. [ABSTRACT FROM AUTHOR]

In this article, we discuss the dynamic wavelength and bandwidth allocation scheme for survivable network architectures and propose a novel fault-tolerant architecture in WDM-EPON, Cost-based Fault-tolerant WDM-EPON (CFT-WDM-EPON), which only equips a backup fiber to provide overall protection for optical components. Furthermore, a Prediction-based Fair Wavelength and Bandwidth Allocation (PFWBA) scheme is also proposed to enhance the differentiated services for WDM-EPON based on Dynamic Wavelength Allocation (DWA) and Prediction-based Fair Excessive Bandwidth Allocation (PFEBA) which is our previous work. The PFEBA involves an Early-DBA mechanism, which improves prediction accuracy by delaying some report messages of unstable traffic ONUs, and assigns linear estimation credit to predict the arrival of traffic during waiting time. The proposed dynamic wavelength allocation scheme can operate in coordination with the unstable degree list to allocate the available time of wavelength precisely. Simulation results demonstrate that the proposed wavelength and bandwidth allocation scheme (PFWBA) is able to provide excellent performance in terms of average delay and delay-variation as compared with other well-known methodologies. [ABSTRACT FROM AUTHOR]

Abstract  Optical networks with DWDM (Dense Wavelength Division Multiplex) can provide multiple data channels to supply high speed, high capacity to perform bandwidth-intensive multicast transmission service. Light-tree is a popular technique applied to support point-to-multipoint multicast services. Any failure during a multicast session would cause severe service loss or disruptions, especially when the faults occur near the source node. A novel ring-based local fault recovery mechanism, Multiple Ring-based Local Restoration (MRLR), for point-to-multipoint multicast traffic based on the minimum spanning tree (MST) in WDM mesh networks is proposed in this article. The MRLR mechanism dismembers the multicast tree into several disjoint segment-blocks (sub-trees) and reserves preplanned spare capacity to set up multiple protection rings in each segment-block for providing rapid local recovery. The MRLR scheme outperforms other methodologies in terms of the blocking probability, recovery time, and average hop count of protection path per session for different network topologies. [ABSTRACT FROM AUTHOR]

Abstract  In general, multicast routing and wavelength assignment (MC-RWA) can be subdivided in routing and wavelength assignment issues in wavelength-division multiplexing (WDM) mesh networks. Previous studies on WDM multicast have mainly focused on WDM multicast routing. The multicast wavelength assignment problem is studied in this paper. A unicast routing path can be established by a lightpath in an all-optical network. However, in the multicasting case, a multicast routing tree can be established by a single light-tree or several lightpaths, or a combination of several light-trees and lightpaths. We propose a wavelength assignment algorithm for finding an optimal combination of lightpaths and light-trees to construct a newly required multicast session. First of all, two cost functions are given to evaluate the establishing cost for each feasible wavelength, and then find a set of wavelengths that covers all destinations with the minimal cost using Integer Linear Programming (ILP) formulation. We focus on maximizing the total number of users served in a multicast session and the network capacity. The simulation results show that the proposed algorithm can improve system resource utilization and reduce the blocking probability compared with the First-Fit algorithm. [ABSTRACT FROM AUTHOR]

Abstract This work describes a distributed fault restoration algorithm, called the Dynamic Multiple Ring Algorithm (DMRA), for application in WDM mesh networks. This study explores the choice of restoration paths and the assignment of fault-tolerant bandwidth when a link, node, or channel failure occurs according to the change in traffic load, number of nodes, and transmission delay including propagation and switching delays. Accordingly, the primary aim of this work is to use networking segments near faults to share the restoration load throughout a mesh network. Each node searches for restoration paths in their near environment using the proposed DMRA. Nodes use distributed control to search for neighboring nodes and to establish the relationship between them to build numerous logical rings. Nodes can also locate faults in the logical rings. These rings establish the restoration paths. The traffic load over failed links or nodes can be diverted to other paths in the networking segments. The cost of the restoration paths is computed at each node based on both the current capacity and the transmission delay. The selected restoration paths are suitable transmission routes in the network neighborhood. Hence, restoration paths can be identified and wavelength assigned quickly according to network bandwidth and traffic load. Simulation results reveal that the proposed method works extremely quickly and has a high success rate. Consequently, it is very useful for applications in real WDM networks, where the status varies from minute to minute. [ABSTRACT FROM AUTHOR]

An ad-hoc wireless network has multihop architecture and is more mobile than single-hop network architecture in the real world. But the ad-hoc wireless network has some challenge with respect to mobility, real-time communication, routing path, maintenance, spatial reuse, bandwidth management, and packets broadcast overhead. This paper investigates two important issues tn ensure more stable path routing and less re-clustering to improve the system performance. Novel Linked Stability-Based Clustering (LSC) and Linked Stability-Based Routing (LSR) algorithms, using fuzzy set theory, are proposed. The LSC algorithm guarantees the stability of the cluster to reduce the probability of re-clustering because the cluster-head is not easily replaced. The LSC algorithm proposed in this paper reduces the easy re-clustering problem of the HCC algorithm by considering not only connectivity but also the link's signal strength between the mobile nodes obtained from a fuzzy set in cluster-head determination. The membership function of the LSC algorithm, based on the link's signal strength, predicts a more stable link routing path using fuzzy set theory. Simulation results show that the proposed algorithm ensures the stability of the cluster and avoids unnecessary re-clustering; for example, the LSC algorithm occurs less frequently than LID and HC algorithms. Similarly, the LSR routing algorithm that uses fuzzy sets and membership functions is based on the mean signal strength and the relative movement between nodes, to obtain the lifetime of each connection and the path lifetime, from fuzzy inferences and fuzzy rules for reference. The LSR algorithm provides more reliable path lifetime and more stable transmission than the table-driven or on-demand approaches. Simulation results reveal that the path lifetime of the LSR algorithm is longer than that of DSR, with a lower probability of path drop and avoiding rerouting. The LSR algorithm has a higher mean number of hoppings, because it always finds the most suitable path and is more stable than DSR, without searching again for a new path when the paths drop. [ABSTRACT FROM AUTHOR]