The space–air–ground integrated network (SAGIN) is considered to be a significant framework for realizing the vision of “6G intelligent connection of all things.” A typical SAGIN consists of three parts: a space-based network composed of various orbiting satellites, an air-based network composed of aircraft, and a traditional ground-based network. Considering the cost of satellite launch, the network needs to be flexible and controllable. In order to ensure that the ground can handle satellite anomalies in real time by program, it is necessary to introduce in-orbit programmable networks, such as the software-defined network (SDN). In the network management architecture, if the controller plane in the SDN adopts the flat management scheme, the expansion of the control plane is limited due to the low efficiency of data synchronization among controllers. Compared with controller deployments on terrestrial networks, multicontroller deployments in the SAGIN face the following problems: the dynamic change of the satellite network topology, the large-scale network nodes, the increase or decrease in the number of aerial vehicles, and the unbalanced distribution of ground users. Therefore, it is of great significance to study how to optimize the deployment of multiple controllers in the SDN-enabled SAGIN. This article introduces an SDN into the SAGIN and designs a hierarchical domain-based SDN-enabled SAGIN architecture. A multicontroller deployment strategy for the hierarchical domain-based SDN-enabled SAGIN is proposed. First, we divide the SDN control plane into two layers, i.e., the primary controller layer is deployed on the ground network and the secondary on the space-based network. The SDN data plane is composed of space-based, air-based, and ground-based networks. Second, considering the average network delay and the controller load, a multiobjective optimization model is constructed. To determine the number of controllers and the relative positions of switch nodes and controllers, the clustering algorithm based on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> -means is adopted to initially divide the data plane. Finally, to improve the global search ability of the algorithm, a multiobjective optimization algorithm based on a genetic algorithm is adopted. The simulation results show that the proposed strategy is effective in reducing the average network delay and improving the controller load balance. Compared to other algorithms, the average network delay is reduced by 13.3% and the controller load is improved by 10.33%. 

Hierarchical Domain-Based Multicontroller Deployment Strategy in SDN-Enabled Space–Air–Ground Integrated Network

From luxury to necessity: Progress of touchless interaction technology

To achieve security of mobile payments within insecure public communication networks, in 2018, a secure transaction scheme for mobile payments is constructed by Yeh from a certificateless signature (CLS) scheme without bilinear pairing Yeh, (2008). However, we point out that this CLS scheme is insecure, and a malicious users can create a valid forged signature on any new message by performing public key replacement attacks. The security flaws of the underlying CLS scheme cause that the upper transaction scheme cannot keep its claimed security. In this article, we describe how this forgery attack works against the CLS scheme, which demonstrates that Yeh’s scheme cannot achieve its original security. Furthermore, to further solve the above-mentioned security flaws, a concrete construction of CLS scheme with improved security is presented. Our improved scheme can be rigorously proved using Forking lemma in the random oracle model, assuming that solving the discrete logarithm problem is infeasible. Finally, a secure transaction scheme for android-based mobile payments is proposed from our improved CLS scheme. 

Improved Secure Transaction Scheme With Certificateless Cryptographic Primitives for IoT-Based Mobile Payments

The space–air–ground integrated network (SAGIN) is considered to be a significant framework for realizing the vision of “6G intelligent connection of all things.” A typical SAGIN consists of three parts: a space-based network composed of various orbiting satellites, an air-based network composed of aircraft, and a traditional ground-based network. Considering the cost of satellite launch, the network needs to be flexible and controllable. In order to ensure that the ground can handle satellite anomalies in real time by program, it is necessary to introduce in-orbit programmable networks, such as the software-defined network (SDN). In the network management architecture, if the controller plane in the SDN adopts the flat management scheme, the expansion of the control plane is limited due to the low efficiency of data synchronization among controllers. Compared with controller deployments on terrestrial networks, multicontroller deployments in the SAGIN face the following problems: the dynamic change of the satellite network topology, the large-scale network nodes, the increase or decrease in the number of aerial vehicles, and the unbalanced distribution of ground users. Therefore, it is of great significance to study how to optimize the deployment of multiple controllers in the SDN-enabled SAGIN. This article introduces an SDN into the SAGIN and designs a hierarchical domain-based SDN-enabled SAGIN architecture. A multicontroller deployment strategy for the hierarchical domain-based SDN-enabled SAGIN is proposed. First, we divide the SDN control plane into two layers, i.e., the primary controller layer is deployed on the ground network and the secondary on the space-based network. The SDN data plane is composed of space-based, air-based, and ground-based networks. Second, considering the average network delay and the controller load, a multiobjective optimization model is constructed. To determine the number of controllers and the relative positions of switch nodes and controllers, the clustering algorithm based on k-means is adopted to initially divide the data plane. Finally, to improve the global search ability of the algorithm, a multiobjective optimization algorithm based on a genetic algorithm is adopted. The simulation results show that the proposed strategy is effective in reducing the average network delay and improving the controller load balance. Compared to other algorithms, the average network delay is reduced by 13.3% and the controller load is improved by 10.33%.

By embedding the state data maintained by the programmable data plane into user packets, the In-band Network Telemetry (INT) can greatly improve the freshness of measured data, such as capturing the micro-bursts in data center networks. However, because the existing INT schemes use fixed telemetry tasks and metadata adding strategies, INT cannot be adjusted in time according to the network state, thus lacking flexibility. To solve the above problems, we propose a Flexible In-band Network Telemetry method FINT. With the designed triple bitmap mechanism, telemetry tasks and parameters can be set dynamically at runtime, which providing flexibility without redeployment to improve telemetry efficiency and reduce the impact of telemetry on network performance. With the designed flexible INT field structure, the types of telemetry metadata carried by user packets can be flexibly selected without significantly adding the indication field. Based on this, to meet the limitation of packet length and reduces the impact on the flow completion time, a greedy telemetry metadata selection algorithm MSG is designed to preferentially select the telemetry metadata with maximum bit-width among the remaining telemetry metadata. The experimental results show that FINT is flexible in adjusting telemetry tasks and add telemetry metadata, and effectively reduce the average flow completion time of the mice flow carrying INT data in the network without significantly increasing the bandwidth consumption. 

FINT: Flexible In-band Network Telemetry method for data center network

We expose the state of the art in the topic of one-way delay measurement in both traditional and software-defined networks. A representative range of standard mechanisms and recent research works, including OpenFlow and Programming Protocol-independent Packet Processors (P4)-based schemes, are covered. We classify them, discuss their advantages and drawbacks, and compare them according to their application environment, accuracy, cost, and robustness. The discussion extends to the reuse of traditional schemes in software-defined networks and the benefits and limitations of the latter with respect to reducing the overhead of network wide measurements. We conclude with a summary of learned lessons and open challenges for future work.

One-Way Delay Measurement From Traditional Networks to SDN: A Survey

Near Field Communication (NFC) technology has been used recently for electronic payment between an Automated Teller Machine (ATM) and a Smartphone. It is threatened by several attacks that can stea...

Djalel Chefrour

Papers

One-Way Delay Measurement From Traditional Networks to SDN: A Survey

Dynamic array PIN:A novel approach to secure NFC electronic payment between ATM and smartphone