The growing pressures of urbanization, vehicular proliferation, and fragmented parking infrastructure pose significant sustainability and mobility challenges in modern cities. In response, we present SPOSChain (Smart Parking Optimization with SDN and Blockchain), a novel Blockchain-enhanced and Software-Defined Networking (SDN)-based smart parking system that unifies independent parking providers under a decentralized, intelligent coordination framework. SPOSChain introduces a four-layer architecture integrating IoT, data, control, and blockchain layers, to ensure transparency, scalability, and real-time responsiveness. The core parking assignment task is formulated as a fairness-driven optimization problem, which is mathematically equivalent to a parallel job scheduling problem, known to be NP-hard, thereby necessitating the development of efficient heuristic strategies. To this end, we propose, adopt, and evaluate multiple heuristic and hybrid algorithms, including Local Search, Branch-and-Bound, and Genetic Search, culminating in a time-aware Hybrid Search model. Simulation results under diverse vehicle arrival distributions (uniform, normal, and exponential) demonstrate that our approach significantly reduces load imbalance, quantified via the Total of Differences metric, while improving responsiveness and maintaining scalability. SPOSChain not only enables equitable and efficient parking allocation but also supports sustainable urban mobility by reducing driver search time, CO 2 emissions, and network overhead. These results underscore the transformative potential of programmable, decentralized parking systems in future smart city infrastructures.

Software-Defined Networking (SDN) and Blockchain (BC) are transformative technologies reshaping network management and security, utilizing their synergies. SDN’s centralized control enhances flexibility and efficiency but introduces vulnerabilities due to its single point of control. With its decentralized and immutable ledger, BC offers a solution by distributing control and providing a tamper-proof audit trail. This paper integrates these technologies to address blackhole attacks—a critical vulnerability where compromised SDN controllers disrupt network performance. We propose Blockchain-Enhanced SDN for Adaptive Path Finding (BeS4APF) algorithm against blackhole attacks in the multidomain SDNs. The algorithm maintains a high Packet Delivery Ratio (PDR) by dynamically adjusting network paths in response to node failures. The BeS4APF algorithm presented effectively maintains a high PDR by dynamically adjusting paths in response to node failures. The methodology involves monitoring the network, detecting compromised nodes, and recalculating optimal paths using Dijkstra’s algorithm and node-disjoint path selection. Experiments with synthetic networks of varying sizes (from 60 to 120 domains) demonstrate that the algorithm successfully handles domain-compromising node attacks, maintaining high PDR even with increasing stochastic disruptions. Our preliminary results show that, while PDR slightly deviates and recovers in smaller networks, it stabilizes towards almost 100% in larger networks after initial adjustments. This work advances the integration of SDN and BC, offering a robust approach to securing modern networks against evolving stochastic attack scenarios and threats.

Huge potentials of optical networks provide an excellent choice in meeting the exponential growth in bandwidth demand. In particular, Elastic Optical Networks (EONs), with its promising potentials in increased availability, failure resilience, load-balancing, new use cases for on-demand opportunities, and efficient resource allocations, are good candidates for the future high-speed networks. When EONs are augmented with the emerging Software Defined Networking (SDN), that decouples the data and control planes, an agile and synergistic combination emerges under a general term of SDN-based optical networking (SDON), albeit with operational challenges. In this paper, we introduce a blockchain-enabled QoS-based inter-Internet Service Provider (ISP) routing coordination framework for SDONs, SpectrumChain (SC), to eliminate centralized mediators and reduce QoS signaling overhead. Experimental results show that the SC framework can effectively handle the QoS-enabled inter-ISP routing in SDON architecture in terms of flow setup time, message overhead, and requests serviced as compared to the traditional approaches.

Data flows of various applications, such as video conferencing, telesurgery, online-gaming, etc., require particular treatment regarding Quality of Service (QoS) because of their sensitivity to such parameters as high bandwidth, low delay, and so on. However, provisioning of QoS-based routing services across Autonomous Systems (ASes) poses gruelling challenges due to the distributed nature and business confidentially hesitations. This study presents a novel blockchain-aided QoS-enabled inter-AS routing framework,QoSChain (QC), by blending merits of Software-Defined Networking (SDN) and Blockchain technologies.QCframework introduces a coordination framework with mutually distrusting participants that eliminates centralized mediators in provisioning QoS among SDN-enabled ASes. Also,QCreduces the time to set up an end-to-end (E2E) path and the number of messages exchanged and processed by SDN controllers for a QoS flow. Furthermore, it alleviates the concerns of network operators regarding potentially sensitive information disclosure resulting from the required information sharing for QoS-based cross-AS paths by masking details of any confidential information. Experimental results verify the feasibility of the proposed framework on E2E QoS-based routing among SDN networks. This work aims at being a useful primer for researchers in providing insights on how blockchain can be deployed in QoS-enabled routing.

With the technology of Network Function Virtualization (NFV), a multicast service (e.g., real-time multimedia streaming or event monitoring) may be accommodated with a Service Function Chain (SFC). The SFC consists of an ordered set of network functions running on generic physical hardware to provide services from source node to each destination node of the multicast service. In this paper, we define the problem of Multicast-aware Service Function Tree Embedding (M-SFTE), which allows the multicast flows to traverse through network service functions before reaching destination nodes. The M-SFTE maps user's SFC-based multicast requests onto a shared substrate network while considering the constraints of network functionality, computing demand of each virtual network function node, and the bandwidth demand of the request. We propose a novel algorithm, called Minimum Cost Multicast Service Function Tree (MC-MSFT) to jointly optimize the process of constructing SFC-based multicast tree and allocating requested resource to embed the tree onto the physical network. The experimental results show that the MC-MSFT algorithm outperforms the traditional greedy-based algorithms as much as by 35% in terms of the total bandwidth consumption.

Network Function Virtualization (NFV) technology decouples network functions from proprietary hardware equipments. As a result, Internet Service Providers (ISPs) implement software-based network functions on generic highvolume substrate network devices. In NFV, a Service Function Chain (SFC) is defined as an ordered set of abstract network functions running on specific substrate nodes (e.g., servers). A challenging issue in NFV management and orchestration is how to optimize the Dependence-aware SFC Embedding in substrate Optical networks (D_SFCE_O). In this paper, we propose a novel algorithm, namely, Dependence-aware SFC embedding with Least-Used consecutive subcarriers (D_SFC_LU), which jointly optimizes SFC design, SFC mapping and spectrum allocation in optical networks. To minimize resource consumption, D_SFC_LU takes advantages of the proposed techniques: Impact Factor based Node Selection (IFNS), Chain Node Mapping (CNM) and Chain-Fit (CF) spectrum allocation. Our simulation and analysis demonstrate that D_SFC_LU can efficiently embed a network requests while minimizing the required substrate resource in optical networks.

In Network Function Virtualization (NFV), Service Function Chain (SFC) is composed of Virtual Network Function (VNF) nodes that are chained via VNF links. SFCs can be specified as unidirectional or bidirectional. A unidirectional SFC (u-SFC) demands the traffic being forwarded via the VNFs in one direction, while a bidirectional SFC (b-SFC) requires bidirectional traffic flows. In this paper, for the first time, we investigate the problem of how to efficiently deploy a hybrid SFC (h-SFC), whereas some VNF nodes are required to process bidirectional traffic while others only handle unidirectional traffic. We define a new problem called hybrid SFC Deployment (h-SFCD). When each substrate node provides one unique VNF, we prove the NP-hardness of the h-SFCD problem and propose an approximate algorithm, namely, 2-approximation Hybrid Service function chain Deployment in Unique function networks (2-HSD-U). Our experimental results show that the proposed 2-HSD-U algorithm significantly outperforms the heuristic algorithm based on the traditional Nearest-Neighbor technique.

Network virtualization in optical networks enables the decoupling of network services from the underlying hardware infrastructure to allow multiple Virtual Optical Requests (VORs) sharing the same Substrate/physical Optical Network (SON). The challenge of mapping VORs onto the shared SON lies on how to efficiently allocate physical resource for the VORs, which is referred to as Virtual Optical Network Embedding (VONE). Many recent research focus on the NP-Hard VONE optimization problem. In this paper, for the first time, we explore how to efficiently map a given VOR for a multicast service onto a shared SON while considering the fanout (splitting/forwarding) limitation of the physical optical switches. We propose a novel algorithm, namely, Centrality-based Degree Bounded Shortest Path Tree (C-DB-SPT) to minimize the resource usage while satisfying the degree limitation in the shared SON. The experimental results show that the C-DB-SPT algorithm outperforms the traditional greedy-based algorithms as much as by 35% in terms of the total bandwidth consumption.

With network virtualization over Elastic Optical Networks (EONs), network services are decoupled from the underlying hardware infrastructure to enable multiple Virtual Optical Requests (VORs) sharing the same Substrate/physical Optical Network (SON). The embedding process of VORs onto the shared SON while satisfying the computing resource and spectrum allocation constraints is referred to Virtual Optical Network Embedding (VONE), which is an NP-Hard problem. In this paper, for the first time, we investigate how to efficiently map a given VOR in the form of virtual optical multicast tree onto an SON. We propose a novel algorithm that is called Impact Factor based Virtual Optical Multicast Tree Embedding (IF-VOMTE) to minimize the resource usage and avoid redundant multicast transmission in the shared SON. The experimental results show that our algorithm outperforms the schemes based on traditional techniques such as Greedy Node Mapping (GNM-SP) and First-Fit Node Mapping (FFNM-SP) in terms of the total cost of bandwidth consumption and the reduction of redundant multicast transmission.

The emerging Network Function Virtualization (NFV) technology decouples network functions from the proprietary hardware, which allows the Internet Service Providers (ISPs) to implement network functions as software running on top of a physical (or substrate) node. With NFV, a Service Function Chain (SFC) is defined as an ordered set of network function instances running on specific substrate network nodes to provide services for client users. In this paper, we define the problem of Dependence- Aware Service Function Chain (D_SFC) design and mapping. We study how to efficiently accommodate user's D_SFC requests in the substrate network while considering the constraints of function dependence, computing demand of virtual nodes and bandwidth demand of the D_SFC. We propose a novel heuristic algorithm, called D_SFC design and resource allocation with Adaptive Mapping (D_SFC_AM), which jointly optimizes the processes of designing a D_SFC and allocating resources requested by the chain. D_SFC_AM employs the proposed techniques of dependence sorting and independent grouping that effectively take into account the node dependence and the resource status of the substrate network. Our experimental results show that the proposed algorithm significantly outperforms the scheme based on the traditional topological sorting in which the process of designing a D_SFC and allocating resources requested by the chain is done sequentially.

Network virtualization enables the decoupling of network services from the underlying hardware infrastructure to allow the same Substrate/physical Network (SN) shared by multiple Virtual Network (VN) requests. The process of mapping virtual nodes and links onto a shared SN while satisfying the computing and bandwidth constraints is referred to Virtual Network Embedding (VNE) as an NP-hard problem. In this paper, for the first time, we explore how to efficiently map a given Virtual Multicast Tree (VMT) request onto a substrate network. We propose a novel algorithm, namely, Virtual Multicast Tree Embedding based on dynamic Impact Factor (VMTE-IF) to minimize the required resource and redundant multicast transmission in the substrate network. The experimental results show that our algorithm outperforms the traditional greedy-based algorithms over 50% in terms of the cost of bandwidth consumption.

In network virtualization, the network services are decoupled from the underlying hardware infrastructure such that multiple virtual network requests can be mapped onto the same physical substrate network. The process of mapping virtual networks onto the substrate network with minimum resources while satisfying the constraints such as computing capacity, bandwidth and memory is referred to as virtual network embedding. In this paper, we investigate how to efficiently map a given virtual network with multicast services. We propose a closeness-centrality based multicast-aware virtual network embedding (CC-MVNE) algorithm to minimize the needed resources for the virtual nodes/links mapping and multicast transmission. Our extensive simulation and analysis show that the proposed approach outperforms the traditional greedy algorithm as much as by 40% in terms of transmission bandwidth consumption.

With the proliferation of the application areas of the Wireless Sensor Networks (WSNs) and the technological advances in sensor electronics, target tracking has become one of the most important functions in WSNs. The overwhelming majority of moving target tracking studies in WSNs has assumed either one-dimensional space (lineland), or two-dimensional domain (flat-land). However, many existing, such as environmental monitoring of rugged terrain, structural health monitoring of buildings, underground and underwater WSN applications, and emerging applications, such as search-and-rescue via Micro Aerial Vehicles, reconnaissance by insect-sized flying robots, need target tracking in three-dimensional space. In this study, we assume a Wireless Aerial Sensor Network (WASN) with conventional low-power and low-complexity features and devise a low spatial and temporal complexity moving target tracking mechanism in 3D based on g-h filter that considers measurement errors. Our prefatory simulations show promising preliminary results for our approach in terms of very low inaccuracy rates between the true location of the target and the forecasts at the sink node as well as negligible estimate errors in terms of Euclidean distance.

The impact of the computing field is becoming more profound everyday in all facets of modern society. Despite significant efforts from academia and relatively high demand for computing, technology producers are needed more than ever. This has been corroborated by a recent NSF Press Release [1], stating that computing is the only STEM discipline with more job openings than college graduates to fill them up. A major responsibility for such an outcome rests upon educators' ability to produce professionals capable of handling ever more complex technical challenges. In this challenging environment, the importance of practical work in science and engineering, supported by lab exercises, is widely known. While it is desirable to create physical laboratories for teaching these technologies, it is not always possible nor desirable. In this paper, we present an effective alternative approach, in the form of an affordable, virtualized laboratory environment that can be used in a variety of computing and engineering courses, as well as in other fields, in lieu of physical labs. Results of a survey supporting the validity of this approach are also presented. Students in four different classes were surveyed concerning the effectiveness and desirability of this virtual laboratory approach. The survey results indicate that student response to and interest in the virtual environment is very strong.