Network anomaly detection is an important and dynamic research area. Many network intrusion detection methods and systems (NIDS) have been proposed in the literature. In this paper, we provide a structured and comprehensive overview of various facets of network anomaly detection so that a researcher can become quickly familiar with every aspect of network anomaly detection. We present attacks normally encountered by network intrusion detection systems. We categorize existing network anomaly detection methods and systems based on the underlying computational techniques used. Within this framework, we briefly describe and compare a large number of network anomaly detection methods and systems. In addition, we also discuss tools that can be used by network defenders and datasets that researchers in network anomaly detection can use. We also highlight research directions in network anomaly detection.

Network Anomaly Detection: Methods, Systems and Tools

Due to the broadcast nature of radio propagation, the wireless air interface is open and accessible to both authorized and illegitimate users. This completely differs from a wired network, where communicating devices are physically connected through cables and a node without direct association is unable to access the network for illicit activities. The open communications environment makes wireless transmissions more vulnerable than wired communications to malicious attacks, including both the passive eavesdropping for data interception and the active jamming for disrupting legitimate transmissions. Therefore, this paper is motivated to examine the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity, and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state of the art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. Several physical-layer security techniques are reviewed and compared, including information-theoretic security, artificial-noise-aided security, security-oriented beamforming, diversity-assisted security, and physical-layer key generation approaches. Since a jammer emitting radio signals can readily interfere with the legitimate wireless users, we also introduce the family of various jamming attacks and their countermeasures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer, and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

/pdf/a-survey-on-wireless-security-technical-challenges-recent-3uamoalvot.pdf

A Survey on Wireless Security: Technical Challenges, Recent Advances, and Future Trends

The use of unmanned aerial vehicles (UAVs) is growing rapidly across many civil application domains, including real-time monitoring, providing wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are the next big revolution in the UAV technology promising to provide new opportunities in different applications, especially in civil infrastructure in terms of reduced risks and lower cost. Civil infrastructure is expected to dominate more than $45 Billion market value of UAV usage. In this paper, we present UAV civil applications and their challenges. We also discuss the current research trends and provide future insights for potential UAV uses. Furthermore, we present the key challenges for UAV civil applications, including charging challenges, collision avoidance and swarming challenges, and networking and security-related challenges. Based on our review of the recent literature, we discuss open research challenges and draw high-level insights on how these challenges might be approached.

Unmanned Aerial Vehicles: A Survey on Civil Applications and Key Research Challenges

This paper examines the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state-of-the-art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. We also introduce the family of various jamming attacks and their counter-measures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

/pdf/a-survey-on-wireless-security-technical-challenges-recent-k705wofne7.pdf

A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends

Smart grid is a promising power delivery infrastructure integrated with communication and information technologies. Its bi-directional communication and electricity flow enable both utilities and customers to monitor, predict, and manage energy usage. It also advances energy and environmental sustainability through the integration of vast distributed energy resources. Deploying such a green electric system has enormous and far-reaching economic and social benefits. Nevertheless, increased interconnection and integration also introduce cyber-vulnerabilities into the grid. Failure to address these problems will hinder the modernization of the existing power system. In order to build a reliable smart grid, an overview of relevant cyber security and privacy issues is presented. Based on current literatures, several potential research fields are discussed at the end of this paper.

https://repository.um.edu.mo/bitstream/10692/2883/3/Liu-2012-Cyber-security-and-privacy-issues-i.pdf

Cyber Security and Privacy Issues in Smart Grids

Space communication protocol standards-transport protocol (SCPS-TP) is a set of extensions to transmission control protocol (TCP) aimed at improving TCP performance over space links. Some work has been done on performance evaluation of SCPS-TP based on its methodology, or by testing it as an isolated entity or over satellite that deploys performance enhancing proxies (PEPs). It is needed to have an experimental evaluation of SCPS-TP in coping with heavy noise using the complete SCPS protocol stack, especially by comparing it with state-of-the-art terrestrial TCP. This paper describes an experimental evaluation of SCPS-TP over congestion free, error-prone, high-latency, point-to-point space links, through file transfer experiment by running the actual SCPS protocol stacks via a testbed. The results reveal that SCPS-TP is more tolerant of heavy noise and has significant throughput advantages over TCP. The performance advantage of SCPS-TP in a lossy link is attributed to its novel SNACK scheme and the advantage in asymmetric channel is from the contributions of the channel rate control and acknowledgment reduction mechanisms.

WLC40-2: An Experimental Evaluation of SCPS-TP over Lossy GEO-Space Links

TCP Vegas is a "proactive" congestion control mechanism which predicts when congestion is about to happen and then reduces the sending rate just before discarding of packets gets started. The techniques of Vegas are expected to be very supportive to space communication which is dominated by frequent packet losses as a result of heavy noise. This is because Vegas is specially designed to minimize packet losses to achieve high throughput. However, very few studies have been done on its usage in space communication. This paper studies the behavior of Vegas over space channel by comparing it over the widely used VJ congestion control using the SGIS test-bed. It is concluded that Vegas achieves much higher throughput than VJ in error prone links such as satellite and wireless channels, which makes it more favorable over VJ in similar environments. It is suggested to use Vegas congestion control mechanism in space and wireless links with similar adverse conditions.

Behavior of Vegas congestion control over satellite channels

The Consultative Committee for Space Data Systems (CCSDS) file delivery protocol, also known as CFDP, is a new standard protocol designed to meet a comprehensive set of file transfer requirements in space communications, especially for deep space missions. However, the performance of CFDP in cislunar space has not yet been evaluated, although the protocol has been particularly developed for deep space communications. In this work, we discuss an experimental investigation of the core file-delivery operation of unreliable CFDP in cislunar space communications. Presented is an experimental performance evaluation of unreliable CFDP operating with reliable transmission control protocol (TCP) and reliable CDFP operating with UDP over the simulated cislunar communication link with intermittent link connectivity.

Experimental Investigation of CCSDS File Delivery Protocol (CFDP) over Cislunar Communication Links with Intermittent Connectivity

Space Communication Protocol Standards - Transport Protocol (SCPS-TP) is a set of extensions to the Transmission Control Protocol (TCP) aimed at improving TCP performance in the space environment. Some work has been done on performance comparison between SCPS-TP and the widely used TCP. It is expected to have an experimental evaluation of the link delay impact on SCPS-TP, especially by comparing it with standard TCP. The paper describes an experimental study of link delay impact on throughput performance of TCP and SCPS-TP. It has been found that the SCPS protocol implementation is less sensitive to link delay variations than the TCP implementation. TCP is highly sensitive, SCPS-VJ is moderately sensitive, and SCPS-Vegas is less sensitive, to the change of link delay.

http://ieeexplore.ieee.org/iel5/9623/30415/01404841.pdf

An experimental evaluation of link delay impact on throughput performance of TCP and SCPS-TP in space communications

Studies of optimal packet size determination in space communication can be found in the literature. However, they are done in an analytical manner. In this paper, we present an experimental study of the cross-layer optimal packet size for a Transmission Control Protocol (TCP) Internet Protocol (IP) enhancement, Space Communication Protocol Standards (SCPS), using a personal computer (PC)-based testbed. We study the optimal packet size at the medium access control (MAC) layer considering the cross-layer interactions at the physical layer. We investigate how the cross-layer MAC packet size needs to be adjusted for optimal throughput performance based on the feedback of the bit-error rate (BER), space-link delay and symmetric/asymmetric channel-rate configurations at the physical channel, and find the cross-layer optimal packet size for the maximum throughput over the space-Internet channels. We find that the default TCP/IP packet size of 1500 bytes for the terrestrial Internet should be chosen as the cross-layer MAC packet size for optimal throughput performance over space channels with round-trip time (RTT) around 250 ms and BER⩽10−6. As the channel BER at the physical layer increases, the optimal MAC packet size should be reduced to around 1000 bytes. We also find that it is more significant to have an optimal packet size for asymmetric channel than symmetric channel but the optimal packet size remains the same at a given BER for both channel ratios in our experiment. To our knowledge, this is the first paper to investigate the cross-layer optimal MAC packet size over space-Internet channel in the proposed approach. Copyright © 2006 John Wiley & Sons, Ltd.

Ruhai Wang

Papers

WLC40-2: An Experimental Evaluation of SCPS-TP over Lossy GEO-Space Links

Behavior of Vegas congestion control over satellite channels

Experimental Investigation of CCSDS File Delivery Protocol (CFDP) over Cislunar Communication Links with Intermittent Connectivity

An experimental evaluation of link delay impact on throughput performance of TCP and SCPS-TP in space communications

An experimental investigation of cross‐layer optimal packet size in space Internet