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Domain name system (DNS) plays a critical part in the functioning of the Internet. But since DNS queries are sent using UDP, it is vulnerable to Distributed Denial of Service (DDoS) attacks. The attacker can take advantage of this and spoof the source IP address and direct the response towards the victim network. And since the network does not keep track of the number of requests going out and responses coming in, the attacker can flood the network with these unwanted DNS responses. Along with DNS, other protocols are also exploited to perform DDoS. Usage of Network Time Protocol (NTP) is to synchronize clocks on systems. Its monlist command replies with 600 entries of previous traffic records. This response is enormous compared to the request. This functionality is used by the attacker in DDoS. Since these attacks can cause colossal congestion, it is crucial to prevent or mitigate these types of attacks. It is obligatory to discover a way to drop the spoofed packets while entering the network to mitigate this type of attack. Intelligent cybersecurity systems are designed for the detection of these attacks. An Intelligent system has AI and ML algorithms to achieve its function. This paper discusses such intelligent method to detect the attack server from legitimate traffic. This method uses an algorithm that gets activated by excess traffic in the network. The excess traffic is determined by the speed or rate of the requests and responses and their ratio. The algorithm extracts the IP addresses of servers and detects which server is sending more packets than requested or which are not requested. This server can be later blocked using a firewall or Access Control List (ACL). [ABSTRACT FROM AUTHOR]

With the development and universal application of satellite technology, an important way to expand the function of satellites is setting up inter-satellite networks to make them work together. Traditional satellite networking methods generally adopt a fixed time slot allocation method, which is not suitable for small satellite groups with low latency and high throughput requirements. In order to solve this problem, it has been proposed to apply the traditional Wifi protocol in satellite networking. As there are differences between satellite networks and terrestrial networks, it’s necessary to improve the traditional 802.11 protocol. The Media Access Control (MAC) protocol in 802.11 is improved in this paper, which mainly includes the adaptive algorithm of maximum contention window size and the growth algorithm of Contention Window (CW) size. The maximum contention window is adjusted according to the conflict state of the current network, which makes the network accommodate more satellite nodes. The CW growth algorithm improves the traditional Binary Exponential Back-off (BEB) algorithm, where the CW is designed according to the priority of the data frame or the network load. In this way, high-priority satellite accusation information will have higher reliability or tolerate greater network load. [ABSTRACT FROM AUTHOR]

The dynamic nature of IEEE802.11 Wireless LAN network poses several challenges in developing a contention resolution scheme. A contention control algorithm guarantees maximum channel throughput by reducing collisions and improves the fairness among competing nodes. Based on the local history and neighbouring station' status, a new algorithm namely Channel Status based Sliding Contention Window (CS-SCW) algorithm is proposed in this paper to adopt the optimum contention window interval. In the proposed algorithm, a fuzzy controller is used to infer about the current channel condition and to regulate the random access in network. Simulation results confirm the enhanced performance of the proposed CS-SCW algorithm in terms of success rate, packet loss, fairness index and energy consumption. [ABSTRACT FROM AUTHOR]

The wireless personal area network (WPAN) is an emerging wireless technology for future short range indoor and outdoor communication applications. The IEEE 802.15.3 medium access control (MAC) is proposed to coordinate the access to the wireless medium among the competing devices, especially for short range and high data rate applications in home networks. In this paper we use analytical modeling to study the performance analysis of WPAN (IEEE 802.15.3) MAC in terms of throughput, efficient bandwidth utilization, and delay with various ACK policies under error channel condition. This allows us to introduce a K-Dly-ACK-AGG policy, payload size adjustment mechanism, and Improved Backoff algorithm to improve the performance of the WPAN MAC. Performance evaluation results demonstrate the impact of our improvements on network capacity. Moreover, these results can be very useful to WPAN application designers and protocol architects to easily and correctly implement WPAN for home networking. [ABSTRACT FROM AUTHOR]

In cognitive radio networks (CRNs), knowledge of the position of the primary users (PUs) is important as it can be used to avoid harmful interference to the primary network while at the same time be exploited to improve the spectrum utilization. In this paper, a semi range-based localization algorithm is proposed for secondary users (SUs) in CRNs to estimate the positions of the PUs. The basic idea of the proposed algorithm is to take advantage of the estimated detection probabilities, which can be obtained from the binary detection indicators of the SUs, to estimate the distances between themselves and the PUs. Moreover, the accuracy of the proposed localization algorithm is further improved by introducing both a weighted least-squares method and an iterative procedure. The Cramer-Rao lower bound (CRLB) of the mean-square error (MSE) of the proposed localization estimator is also derived. A scenario with malicious users (MUs) is further considered, where the proposed method is modified to detect MUs. To illustrate the benefits of localization, we design a location-aware medium access control (MAC) protocol and show that significant throughput gains can be realized over conventional MAC protocols. [ABSTRACT FROM AUTHOR]

In recent years, the incorporation of the directional antennas within mobile devices has been studied in many areas. The usage of directional antennas can greatly reduce the radio interference, which results in improved utilization of the wireless medium. It becomes practical to exploit the directional antennas in the medium-access control (MAC) protocol design. In this paper, a location- and mobility-aware (LMA) MAC protocol is developed for vehicular ad hoc networks (VANETs). The predictive location and mobility of the vehicles are adopted to provide robust communication links while using the directional beams. The deafness problem is also alleviated using the directional-listen mechanism in the proposed algorithm. Moreover, the exploitation of the directional beacons within the scheme can enhance the reliability of the communication linkages, even when the moving directions and speeds of the vehicles have been changed. Under dynamic moving scenarios, both the spatial reuse and the routing efficiency are preserved using the proposed LMA MAC scheme. The performance of the proposed algorithm is evaluated and compared with other existing MAC protocols in simulations. [ABSTRACT FROM AUTHOR]

Media Access Control (MAC) protocol based on Carrier Sense Multiple Access (CSMA) with bounded packet delay for each priority is useful for real-time and emergent use. In this paper, a CSMA based protocol with multiple priorities for home automation network is proposed to ensure Controllable Mean Packet Delay (CMPD) for all priorities under heavy traffic load A Transmission Ratio Assignable (TRA) algorithm is used to achieve CMPD for each priority. Analysis of the TRA algorithm is presented, and a CMPD theorem is proved that the CMPD is inversely proportional to the assigned successful transmission ratio for all priorities. It is meaningful because the CMPD can be controlled by assigning different successful transmission ratio to different priorities. Furthermore, simulation results demonstrate that the TRA algorithm and the CMPD theorem are correct. [ABSTRACT FROM AUTHOR]