IET Networks最新文献

Solar cells are increasingly being utilised for both energy harvesting and reception in free-space optical (FSO) communication networks. The authors focus on the implementation of a mid-band p-In_0.01Ga_0.99 N/p-In_0.5Ga_0.5 N/n-In_0.5Ga_0.5 N (PPN) solar cell, boasting an impressive 26.36% conversion efficiency (under 1.5AM conditions) as a receiver within an indoor FSO communication network. Employing a solar cell with dimensions of 1 mm in length and width, the FSO system underwent simulation using Optisystm software, while the solar cell's behaviour was simulated using SCAPS-1D. The received power from the solar cell was then compared to that of four commercially available avalanche photodiode (APD) receivers. Exploring incident wavelengths spanning 400–700 nm within the visible spectrum, across transmission distances of 5, 10, 15, and 20 m, the study presented current-voltage (IV) and power-voltage curves. Notably, the InGaN solar cell exhibited superior electrical power output compared to all commercial APDs. In conclusion, the findings underscore that augmenting received power has the potential to enhance FSO network quality and support extended transmission distances.

Open Shortest Path First (OSPF) currently supports multiarea networking with two severe limitations: the multiarea topology is restricted to a two-level hierarchy, and globally optimal routing may not be achieved. An OSPF extension that overcomes these limitations is proposed by introducing a routing overlay for the dissemination of multiarea routing information. It applies to both OSPFv2 (IPv4) and OSPFv3 (IPv6) and is transparent to area-internal routers. The extension was fully implemented and tested, and the results show that the added functionality is completely achieved, at the cost of a small penalty in terms of convergence times for small networks.

Cybersecurity events occur frequently. When it comes to investigating security threats, it is essential to offer a 100 percent accurate and packet-level network history, which depends on packet capture with high precision packet timestamping. Many packet capture applications are developed based on data plane development kit (DPDK)—a set of libraries and drivers for fast packet processing. However, DPDK cannot give an accurate timestamp for every packet, and it is unable to truly reflect the order in which packets arrive at the network interface card. In addition, DPDK-based applications cannot achieve zero packet loss when the packet is small such as 64 B for beyond 10 Gigabit Ethernet. Therefore, the authors proposed a new method based on Field-Programmable Gate Array (FPGA) to solve this problem. The authors also develop a DPDK driver for FPGA devices to make the design compatible with all DPDK-based applications. The proposed method performs timestamping at line-rate for 10 Gigabit Ethernet traffic at 4 ns precision and 1 ns precision for 25 Gigabit, which greatly improves the accuracy of security incident retrospective analysis. Furthermore, the design can capture full-size packets for any protocol with zero packet loss and can be applied to 40/100 Gigabit systems as well.

B5G/6G networks are facing challenges in the deployment of additional base stations. However, Taiwan's four major operators have launched VoWi-Fi calling services to maintain signal quality and coverage for customers. These services pose potential threats when users connect to untrusted Wi-Fi networks. Therefore, the authors utilised commercial equipment to study the security of VoWi-Fi calling services offered by Taiwan's four major telecom companies. The authors employed address resolution protocol attack methods to develop two verification attacks that bypass existing security measures: one for dropping session initiation protocol packets and the other for dropping voice call packets, both capable of circumventing current security defences. Through real-world experiments, the authors confirmed their feasibility and assessed their potential harm. Consequently, two defence methods are proposed. The first is an anti-attack algorithm for app and device manufacturers to detect the security of the user's calling environment. The second is a recommendation for telecom operators to implement new detection mechanisms to safeguard user rights.

The cover image is based on the Case Study VoWi-Fi security threats: Address resolution protocol attack and countermeasures by Kuan-Chu Lu et al., https://doi.org/10.1049/ntw2.12113

The enhanced capacity of optical networks is a significant advantage within the global telecommunications industry. Optical networks provides transmission of information over large distances with reduced latency. However, the growing intricacy of network topologies poses a significant challenge to network adaptability, network resilience, device compatibility, and service quality in the contemporary era of technology and 5G networks. In light of these challenges, recent studies leverages on disaggregation in the context of Software Defined Network (SDN) and network service orchestrators as a viable remedy. Disaggregated optical systems offer SDON (Software-Defined Optical Networking) enhanced control options and third-party dynamism streamlining upgrades and diminishing single vendor dependency. Although, the advancement of disaggregation improves network flexibility and vendor neutrality of Software Defined Optical Networking (SDON), this improvement comes at the cost of reduced scalability and network controllability performance. The current research paper posits two potential resolutions to the aforementioned challenge. The authors present recommendations and an enhanced architecture that leverages Open Network Operating System (ONOS) containers and Kubernetes orchestration to improve scalability inside the Software-Defined Optical Networking (SDON) architecture. The suggested architectural design has underlining novel flow charts and algorithms that enhances scalability performance by 33% while also preserving flexibility and controllability in comparison to pre-existing SDON architectures. This architecture also makes use of the Mininet-Optical physical-layer architecture to simulate a real-time scenario, as well as yang models from the Open Disaggregated Transport Network (ODTN) working group, the pioneers of SDONs. A detailed analysis of the rules and procedural processes involved in the implementation of the proposed architecture. In order to demonstrate the practical application of this architectural framework to a real-world Software-Defined Optical Network (SDON) system, the pre-existing SDON ONOS architecture within the Optical Transport Domain Networking (OTDN) working group was adjusted and refined. This adaptation aimed to illustrate the use of ONOS in conjunction with established optical network systems, highlighting the advantages it offers.

Wireless virtual network uses software defined network and network function virtualisation technologies to create multiple logically isolated virtual networks on a physical wireless network. Wireless virtual network can improve the utilisation of wireless resources to meet the requirements of different services. Delay is an important performance indicator, which has strict requirements for delay-sensitive services such as video conferencing and online games. In this study, a virtual network embedding method based on node delay perception (VNE-NDP) is proposed, which considers both the node and link resources as well as the embedding delay requirements of virtual networks. The virtual network embedding method based on node delay perception consists of two phases: virtual node embedding and virtual link embedding. In the virtual node embedding phase, a physical node sorting method based on node delay perception (PNS-NDP) is proposed. In PNS-NDP, the node deployment delay is introduced into the node sorting algorithm for the first time. The authors select candidate physical nodes for each virtual node according to their resource availability and delay performance, which can greatly reduce the VN embedding delay without sacrificing too much other performance. In the virtual link embedding phase, a shortest path algorithm with bandwidth and link deployment delay constraints to find feasible physical paths for each virtual link is used. In addition, the VN embedding (VNE) deployment time is set as a new evaluation index. Simulation results show that compared with other VNE methods, VNE-NDP can achieve higher success rate, revenue-to-expenditure ratio, and lower deployment delay.

A low complexity resource allocation method is proposed for downlink non-orthogonal multiple access system assisted by intelligent reflecting surface (IRS). Firstly, an optimisation problem is formulated to minimise power consumption, with power allocation and IRS phase shifts as variables. Then, the joint optimisation problem of power allocation and IRS phase shifts is transformed into the optimisation of IRS phase shifts, which is further decomposed into multiple single variable sub-problems, the solutions to which can be obtained by using the function extremum method. Next, based on these sub-problems, one-level iterative algorithm is developed to optimise IRS phase shifts. Finally, the minimum power required by each user is calculated based on the IRS phase shifts obtained through iteration. Simulation results show that the proposed scheme is better than the existing schemes in the same scenario under the same rate requirement in terms of computational complexity and power consumption.