Biblio

As Internet of Things(IOT) devices become intelli-gent, more powerful computing capability is required. Multi-core processors are widely used in IoT devices because they provide more powerful computing capability while ensuring low power consumption. Therefore, it requires the operating system on IoT devices to support and optimize the scheduling algorithm for multi-core processors. Nowadays, microkernel-based operating systems, such as QNX Neutrino RTOS and HUAWEI Harmony OS, are widely used in IoT devices because of their real-time and security feature. However, research on multi-core scheduling for microkernel operating systems is relatively limited, especially for load balancing mechanisms. Related research is still mainly focused on the traditional monolithic operating systems, such as Linux. Therefore, this paper proposes a low-latency, high- performance, and high real-time centralized global dynamic multi-core load balancing method for the microkernel operating system. It has been implemented and tested on our own microkernel operating system named Mginkgo. The test results show that when there is load imbalance in the system, load balancing can be performed automatically so that all processors in the system can try to achieve the maximum throughput and resource utilization. And the latency brought by load balancing to the system is very low, about 4882 cycles (about 6.164us) triggered by new task creation and about 6596 cycles (about 8.328us) triggered by timing. In addition, we also tested the improvement of system throughput and CPU utilization. The results show that load balancing can improve the CPU utilization by 20% under the preset case, while the CPU utilization occupied by load balancing is negligibly low, about 0.0082%.

The steady growing trend of user demand in using various 4G mobile broadband applications obligates telecom operators to thoroughly plan a precise Quality of Service (QoS) contract with its subscribers. This directly reveals a challenge in figuring out a sophisticated behavior of radio resources (RBs) at the base station to effectively handle the oscillated loads to fulfill their QoS profiles. This paper elaborates on the above issue by analyzing the behavior of the downlink packet scheduling scheme and proposes a solution to bridge between the two major QoS indicators for Real-Time (RT) services, that are, throughput and delay. The proposed scheduling scheme emphasizes that a prior RBs planning indeed has an immense impact on the behavior of the deployed scheduling rule, particularly, when heterogeneous flows share the channel capacity. System-level simulations are performed to evaluate the proposed scheduling scheme in a comparative manner. The numerical results of throughput and delay assured that diverse QoS profiles can be satisfied in case of considering RBs planning.

MANET stands for Mobile ad-hoc network, which is also known as a wireless network. It provides a routable networking environment which does not have a centralized infrastructure. MANET is used in many important sectors like economic sector (corporate field), security sector (military field), education sector (video conferences and lectures), law sector (law enforcement) and many more. Even though it plays a vital role in different sectors and improves its economic growth, security is a major concern in MANET. Due to lack of inbuilt security, several attacks like data traffic attack, control traffic attack. The wormhole is a kind of control traffic attack which forms wormhole link between nodes. In this paper, we have proposed an approach to detect and get rid of the wormhole attack. The proposed approach is based on trust values, which will decide whether nodes are affected by using parameters like receiving time and data rate. On evaluation, we have concluded that the wormhole attack decreases the network's performance while using trusted approach its value increases. Means PDR and throughput return best results for the affected network while in case of end to end delay it returns similar results as of unaffected network.

In Mobile Ad-hoc Network based Internet of things (MANET-IoT), nodes are mobile, infrastructure less, managed and organized by themselves that have important role in many areas such as Mobile Computing, Military Sector, Sensor Networks Commercial Sector, medical etc. One major problem in MANET based IoT is security because nodes are mobile, having not any central administrator and are also not reliable. So, MANET-IoT is more defenseless to denial-of-service attacks for-example Blackhole, Wormhole, Gray-hole etc. To compare the performance of network under different attacks for checking which attack is more affecting the performance of network, we implemented Blackhole and Wormhole attack by modifying AODV routing protocol in NS-3. After preprocessing of data that is obtained by using Flow-monitor module, we calculated performance parameters such as Average Throughput, Average Packet Delivery Ratio, Average End to End Delay, Average Jitter-Sum and compared it with no. of nodes in MANET-IoT network. Throughput and goodput performance of each node in the network is also calculated by using Trace metric module and compared with each node in the network. This approach is also very helpful for further research in MANET-IoT Security.

Mobile Ad Hoc Network (MANET) is one of the types of Ad-hoc Network which is comprised of wireless in a network. The main problem in this research is the vulnerability of the protocol routing Dymo against jellyfish attack, so it needs detection from a jellyfish attack. This research implements the DELPHI method to detect jellyfish attacks on a DYMO protocol which has better performance because the Delay Per-Hop Indicator (DELPHI) gathers the amount of hop and information delay from the disjoint path and calculates the delays per-hop as an indicator of a jellyfish attack. The evaluation results indicate an increase in the end-to-end delay average, start from 112.59s in 10 nodes increased to 143.732s in 30 nodes but reduced to 84,2142s in 50 nodes. But when the DYMO routing did not experience any jellyfish attacks both the delivery ratio and throughput are decreased. The delivery ratio, where decreased from 10.09% to 8.19% in 10 nodes, decreased from 20.35% to 16.85%, and decreased from 93.5644% to 82.825% in 50 nodes. As for the throughput, for 10 nodes decreased from 76.7677kbps to 68.689kbps, for 30 nodes decreased from 100kbps to 83.5821kbps and for 50 nodes decreased from 18.94kbps to 15.94kbps.

High throughput of crypto circuit is critical for many high performance security applications. The proposed SM3 circuit design breaks the inherent limitation of the conventional algorithm flow by removing the "blocking point" on the critical path, and reorganizes the algebraic structure by adding four parallel compensation operations. In addition, the round expansion architecture, CSA (Carry Save Adder) and pre-calculation are also used in this design. Due to the optimization at both the algorithm level and the circuit level, the synthesized circuit of this design can reach maximum 415MHz operating clock frequency and 6.4Gbps throughput with SMIC 40nm high performance technology. Compared with the conventional implementation method, the throughput performance of the proposed SM3 circuit increases by 97.5% and the chip area of SM3 algorithm area is only increased by 16.2%.

Cloud computing adoption is on the rise. Many organizations have decided to shift their workload to the cloud to benefit from the scalability, resilience, and cost reduction characteristics. Mobile Cloud Computing (MCC) is an emerging computing paradigm that also provides many advantages to mobile users. Mobile devices function on wireless internet connectivity, which entails issues of limited bandwidth and network congestion. Hence, the primary focus of Web applications in MCC is on improving performance by quickly fulfilling customer's requests to improve service satisfaction. This paper investigates a new approach to caching data in these applications using Redis, an in-memory data store, to enhance Quality of Service. We highlight the two implementation approaches of fetching the data of an application either directly from the database or from the cache. Our experimental analysis shows that, based on performance metrics such as response time, throughput, latency, and number of hits, the caching approach achieves better performance by speeding up the data retrieval by up to four times. This improvement is of significant importance in mobile devices considering their limitation of network bandwidth and wireless connectivity.

Due to its minimal price and expandable wireless open system interconnection options for the coming years, wireless mesh networking is appealing, developing, and novel medium of speech, which is why it is becoming a somewhat widely used communication field. In all network types, one of the essential factors for prevalent and trustworthy communication is cybersecurity. The IEEE 802.11 working gathering has created various correspondence guidelines. Yet, they are by and by focusing on the 802.11s standard because of its dynamic setup and geography learning abilities. Information, voice, and directions are steered between hubs employing remote lattice organising. WMNs incidentally give nearby 802.11g admittance to customers and connection neighbours utilising 802.11a "backhaul," but this isn’t generally the situation because of changing requirements, for example, top information rate and inclusion range. The small cross-sectional organisation emerged as a fundamental innovation to enable broadband system management in large regions. It benefits specialised organisations by reducing the cost of sending networks and end customers by providing ubiquitous Internet access anywhere, anytime. Given the idea of wireless mesh networking and the lack of integrated organisational technology, small grid networks are powerless against malicious attacks. In the meantime, the limit of multi-radio multi-channel correspondence, the need for heterogeneous organisation coordination, and the interest for multi-bounce remote equality often render conventional security strategies ineffectual or challenging to carry out. Thus, wireless mesh networking presents new issues that require more viable and relevant arrangements. WMNs have piqued the curiosity of both scholastics and industry because of their promising future. Numerous testbeds are built for research purposes, and business items for veritable WMNs are accessible. Anyway, a few concerns should be cleared up before they can very well become widespread. For example, the accessible MAC and routing conventions are not customisable; the throughput drops impressively with an increasing number of hubs or bounces in WMNs. Because of the weakness of WMNs against various malicious attacks, the security and protection of correspondence is a serious concern. For example, enemies can sniff long-distance correspondence to obtain sensitive data. Attackers can carry out DoS attacks and control the substance of the information sent through compromised hubs, thereby endangering the company’s secret, accessibility authenticity, and integrity. WMNs, like compact Impromptu Organisations (MANETs), share a typical medium, no traffic aggregate point, and incredible topography. Due to these restrictions, normal safety frameworks in wired associations can’t be quickly applied to WMNs. Also, the techniques utilised in MANETs are not viable with WMNs. This is because of the manner in which WMNs expand MANETs in different ways. Framework centres are generally outfitted with an assortment of radios. Then, at that point, many channels are doled out to every centre to work with concurrent data move and diversity.

Securing data, management of the authorised access of the user and maintaining the privacy of the data are some of the problems relating with the stored data in the database. The security of the data stored is considered as the major concern which is to be managed in a very serious manner as the users are sensitive about their shared data. The user's data can be protected by the process of cryptography which is considered as the conventional method. Advanced Encryption Standard (AES), Data Encryption Standard(DES), Two Fish, Rivest Shamir Adleman Algorithm (RSA), Attribute Based Encryption (ABE), Blowfish algorithms are considered as some of the cryptographic algorithms. These algorithms are classified into symmetric and asymmetric algorithms. Same key is used for the encryption and decoding technique in symmetric key cryptographic algorithm whereas two keys are used for the asymmetric ones. In this paper, the implementation of one of the asymmetric algorithm RSA with the educational dataset is done. To secure the distributed database, the extended version of the RSA algorithm is implemented as the proposed work.

Software Defined Network (SDN) is a new paradigm in network architecture. The basic concept of SDN itself is to separate the control plane and forwarding plane explicitly. In the last few years, SDN technology has become one of the exciting topics for researchers, the development of SDN which was carried out, one of which was implementing the Internet of Things (IoT) devices in the SDN network architecture model. Mininet-IoT is developing the Mininet network emulator by adding virtualized IoT devices, 6LoWPAN based on wireless Linux standards, and 802.15.4 wireless simulation drivers. Mininet-IoT expands the Mininet code class by adding or modifying functions in it. This research will discuss the performance of the 6LoWPAN device on the internet of things (IoT) network by applying the SDN paradigm. We use the Mininet-IoT emulator and the Open Network Operating System (ONOS) controller using the internet of things (IoT) IPv6 forwarding. Performance testing by comparing some of the topologies of the addition of host, switch, and cluster. The test results of the two scenarios tested can be concluded; the throughput value obtained has decreased compared to the value of back-traffic traffic. While the packet loss value obtained is on average above 15%. Jitter value, delay, throughput, and packet loss are still in the category of enough, good, and very good based on TIPHON and ITU-T standards.

Routing protocol for low power and lossy networks (RPL) is a fundamental routing protocol of 6LoWPAN, a centre correspondence standard for the Internet of Things. RPL outplay other wireless sensor and ad hoc routing protocols in the aspect of service (QoS), device management, and energy-saving performance. The Rank definition in RPL addresses several issues, such as path optimization, loop avoidance, and power overhead management. RPL rank and version number attacks are two types of the most common forms of RPL attacks, may have crucial ramification for RPL networks. The research directed upon these attacks includes considerable vulnerabilities and efficiency issues. The rank attack on sensor networks is perhaps the utmost common, posing a challenge to network connectivity by falling data or disrupting routing routes. This work presents a rank attack detection system focusing on RPL. Considering many of such issues a method has been proposed using spatial correlation function (SCF) and Dijkstra's algorithm considering parameters like energy and throughput.

In MANET's (MOBILE Adhoc Network), the origin node will communicate the target node with the help of in-between nodes by Multi-hop communication to save power [1]. Thus, the main objective in MANETs is to identify the feasible route such that the parcels of the data can be done in an organized manner. So, the nodes in the selected route are honest and reliable. However, bad behavior nodes may affect routing performance. This work aims to discover the route does not have egotistic nodes, i.e., nodes which having honest & energy are less not considered for the route between origin and target. The proposed procedure holds the input from the end-user and results in the boundary values i.e. avg. throughput, appropriateness and drop fraction of egotistic nodes were stored in a result location. After the simulation, the discovered route by using the proposed protocol improves the overall network performance for output parameters.

RPL, the IPv6 Routing Protocol for low-power and lossy networks, was standardized by the Internet Engineering Task Force (IETF) in 2011. It is developed to connect resource constrained devices enabled by low-power and lossy networks (LLNs). RPL prominently becomes the routing protocol for IoT. However, the RPL protocol is facing many challenges such as trustworthiness among the nodes which need to be addressed and resolved to make the network secure and efficient. In this paper, a multicasting technique is developed that is based on trust mechanism to resolve this issue. This mechanism manages and protects the network from untrusted nodes which can hamper the security and result in delayed and distorted transmission of data. It allows any node to decide whether to trust other nodes or not during the construction of the topology. This is then proved efficient by comparing it with broadcasting nature of the transmission among the nodes in terms of energy, throughput, percentage of alive and dead nodes.

Opportunistic routing (OR) is gaining popularity in low-duty wireless sensor network (WSN), so the need for efficient and reliable data transmission is becoming more essential. Reliable transmission is only feasible if the routing protocols are secure and efficient. Due to high energy consumption, current cryptographic schemes for WSN are not suitable. Trust-based OR will ensure security and reliability with fewer resources and minimum energy consumption. OR selects the set of potential candidates for each sensor node using a prioritized metric by load balancing among the nodes. This paper introduces a trust-based load-balanced OR for duty-cycled wireless sensor networks. The candidates are prioritized on the basis of a trusted OR metric that is divided into two parts. First, the OR metric is based on the average of four probability distributions: the distance from node to sink distribution, the expected number of hops distribution, the node degree distribution, and the residual energy distribution. Second, the trust metric is based on the average of two probability distributions: the direct trust distribution and the recommended trust distribution. Finally, the trusted OR metric is calculated by multiplying the average of two metrics distributions in order to direct more traffic through the higher priority nodes. The simulation results show that our proposed protocol provides a significant improvement in the performance of the network compared to the benchmarks in terms of energy consumption, end to end delay, throughput, and packet delivery ratio.

Industry is increasingly adopting Reinforcement Learning algorithms (RL) in production without thoroughly analyzing their security features. In addition to the potential threats that may arise if the functionality of these algorithms is compromised while in operation. One of the well-known RL algorithms is the Contextual Multi-Armed Bandit (CMAB) algorithm. In this paper, we explore how the CMAB can be used to solve the Link Adaptation problem - a well-known problem in the telecommunication industry by learning the optimal transmission parameters that will maximize a communication link's throughput. We analyze the potential vulnerabilities of the algorithm and how they may adversely affect link parameters computation. Additionally, we present a provable security assessment for the Contextual Multi-Armed Bandit Reinforcement Learning (CMAB-RL) algorithm in a network simulated environment using Ray. This is by demonstrating CMAB security vulnerabilities theoretically and practically. Some security controls are proposed for CMAB agent and the surrounding environment. In order to fix those vulnerabilities and mitigate the risk. These controls can be applied to other RL agents in order to design more robust and secure RL agents.

Adapting parallel scheduling function in the design of multi-scheduling algorithm results significant impact in the operation of high performance parallel systems. The various methods of parallelizing scheduling functions are widely applied in traditional multiprocessor systems. In this paper a novel algorithm is introduced which works not only for parallel execution of jobs but also focuses the parallelization of scheduling function. It gives attention on reducing the execution time, minimizing the load balance performance by selecting the volume of tasks for migration in terms of packets. Jobs are grouped into packets consisting of 2n jobs which are scheduled in parallel. Thus, an enhancement in the scheduling mechanism by packet formation is made to carry out high utilization of underlying architecture with increased throughput. The proposed method is assessed on a desktop computer equipped with multi-core processors in cube based multiprocessor systems. The algorithm is implemented with different configuration of multi-core systems. The simulation results indicate that the proposed technique reduces the overall makespan of execution with an improved performance of the system.

Mobile Adhoc networks (MANETs) comprises of mobile devices or nodes that are connected wirelessly and have no infrastructure. Detecting malicious activities in MANETs is a challenging task as they are vulnerable to attacks where the performance of the entire network degrades. Hence it is necessary to provide security to the network so that the nodes are prone to attack. Selecting a good routing protocol in MANET is also important as frequent change of topology causes the route reply to not arrive at the source node. In this paper, R-AODV (Reverse Adhoc On-Demand Distance Vector) protocol along with ECC (Elliptic Key Cryptography) algorithm is designed and implemented to detect and to prevent the malicious node and to secure data transmission against blackhole attack. The main objective is to keep the data packets secure. ECC provides a smaller key size compared to other public-key encryption and eliminates the requirement of pre-distributed keys also makes the path more secure against blackhole attacks in a MANET. The performance of this proposed system is simulated by using the NS-2.35 network simulator. Simulation results show that the proposed protocol provides good experimental results on various metrics like throughput, end-to-end delay, and PDR. Analysis of the results points to an improvement in the overall network performance.

Wireless sensors are often deployed in environments where it is difficult for them to discern friend from enemy. An example case is a military tactical scenario, where sensors are deployed to map the location of an item but where some of the nodes have been compromised or where there are other malicious nodes present. In this scenario, sharing data with other network nodes may present a critical security risk to the sensor nodes. Blockchain technology, with its ability to house a secure distributed ledger, offers a possible solution. However, blockchain applications for Wireless Sensor Networks suffer from poor latency in block propagation which in turn decreases throughput and network scalability. Several researchers have proposed solutions for improved network throughput. In this work, a comparison of these existing works is performed leading to a taxonomy of existing algorithms. Characteristics consistently found in algorithms reporting improved throughput are presented and, later, these characteristics are used in the development of a new algorithm for improving throughput. The proposed algorithm utilizes a proof-of- authority consensus algorithm with a node trust-based scheme. The proposed algorithm shows strong results over the base case algorithm and was evaluated with blockchain network simulations of up to 20000 nodes.

As the core infrastructure of cloud data operation, exchange and storage, data centerneeds to ensure its security and reliability, which are the important prerequisites for the development of cloud computing. Due to various illegal accesses, attacks, viruses and other security threats, it is necessary to protect the boundary of cloud data center through security gateway. Since the traffic growing up to gigabyte level, the secure gateway must ensure high transmission efficiency and different network services to support the cloud services. In addition, data center is gradually evolving from IPv4 to IPv6 due to excessive consumption of IP addresses. Packet classification algorithm, which can divide packets into different specific streams, is very important for QoS, real-time data stream application and firewall. Therefore, it is necessary to design a high performance IPv6 packet classification algorithm suitable for security gateway.AsIPv6 has a128-bitIP address and a different packet structure compared with IPv4, the traditional IPv4 packet classification algorithm is not suitable properly for IPv6 situations. This paper proposes a fast packet classification algorithm for IPv6 - PCHA (packet classification based on hash andAdelson-Velsky-Landis Tree). It adopts the three flow classification fields of source IPaddress(SA), destination IPaddress(DA) and flow label(FL) in the IPv6 packet defined by RFC3697 to implement fast three-tuple matching of IPv6 packet. It is through hash matching of variable length IPv6 address and tree matching of shorter flow label. Analysis and testing show that the algorithm has a time complexity close to O(1) in the acceptable range of space complexity, which meets the requirements of fast classification of IPv6 packetsand can adapt well to the changes in the size of rule sets, supporting fast preprocessing of rule sets. Our algorithm supports the storage of 500,000 3-tuple rules on the gateway device and can maintain 75% of the performance of throughput for small packets of 78 bytes.

While we cannot question the high performance capabilities of the kernel bypass approach in the network functions world, we recognize that the Linux kernel provides a rich ecosystem with an efficient resource management and an effective resource sharing ability that cannot be ignored. In this work we argue that by mixing kernel-bypass and in kernel processing can benefit applications and network function middleboxes. We leverage a high-performance user space TCP stack and recent additions to the Linux kernel to propose a hybrid approach (kernel-user space) to accelerate SDN/NFV deployments leveraging services of the reliable transport layer (i.e., stateful middleboxes, Layer 7 network functions and applications). Our results show that this approach enables highperformance, high CPU efficiency, and enhanced integration with the kernel ecosystem. We build our solution by extending mTCP which is the basis of some state-of-the-art L4-L7 NFV frameworks. By having more efficient CPU usage, NFV applications can have more CPU cycles available to run the network functions and applications logic. We show that for a CPU intense workload, mTCP/AF\_XDP can have up to 64% more throughput than the previous implementation. We also show that by receiving cooperation from the kernel, mTCP/AF\_XDP enables the creation of protection mechanisms for mTCP. We create a simulated DDoS attack and show that mTCP/AF\_XDP can maintain up to 287% more throughput than the unprotected system during the attack.

As the unmanned aerial vehicle (UAV) can play a vital role to collect information remotely in a military battlefield, researchers have shown great interest to reveal the domain of internet of battlefield Things (IoBT). In a rescue mission on a battlefield, UAV can collect data from different regions to identify the casualty of a soldier. One of the major challenges in IoBT is to identify the soldier in a complex environment. Image processing algorithm can be helpful if proper methodology can be applied to identify the victims. However, due to the limited hardware resources of a UAV, processing task can be handover to the nearby edge computing server for offloading the task as every second is very crucial in a battlefield. Furthermore, to avoid any third-party interaction in the network and to store the data securely, blockchain can help to create a trusted network as it forms a distributed ledger among the participants. This paper proposes a UAV assisted casualty detection scheme based on image processing algorithm where data is protected using blockchain technology. Result analysis has been conducted to identify the victims on the battlefield successfully using image processing algorithm and network issues like throughput and delay has been analyzed in details using public-key cryptography.

Throughout the Department of Defense, there are ongoing efforts to increase cybersecurity and improve data transfer in unmanned robotic systems (UxS). This paper explores the performance of the Robot Operating System (ROS) 2, which is built with the Data Distribution Service (DDS) standard as a middleware. Based on how quality of service (QoS) parameters are defined in the robotic middleware interface, it is possible to implement strict delivery requirements to different nodes on a dynamic nodal network with multiple unmanned systems connected. Through this research, different scenarios with varying QoS settings were implemented and compared to baseline values to help illustrate the impact of latency and throughput on data flow. DDS security settings were also enabled to help understand the cost of overhead and performance when secured data is compared to plaintext baseline values. Our experiments were performed using a basic ROS 2 network consisting of two nodes (one publisher and one subscriber). Our experiments showed a measurable latency and throughput change between different QoS profiles and security settings. We analyze the trends and tradeoffs associated with varying QoS and security settings. This paper provides performance data points that can be used to help future researchers and developers make informative choices when using ROS 2 for UxS.

Mobile Ad hoc networks (MANET) are becoming extremely popular because of the expedient features that also make them more exposed to various kinds of security attacks. The Wormhole attack is considered to be the most unsafe attack due to its unusual pattern of tunnel creation between two malevolent nodes. In it, one malevolent node attracts all the traffic towards the tunnel and forwards it to another malevolent node at the other end of the tunnel and replays them again in the network. Once the Wormhole tunnel is created it can launch different kind of other attacks such as routing attack, packet dropping, spoofing etc. In past few years a lot of research is done for securing routing protocols. Dynamic Source Routing (DSR) protocol is considered foremost MANET routing protocols. In this paper we are forming the wormhole tunnel in which malevolent nodes use different interfaces for communication in DSR protocol. NS3 simulator is being used for the analysis of the DSR routing protocol under the wormhole attack. This paper provides better understanding of the wormhole attack in DSR protocol which can benefit further research.

Classification of Misbehaving Nodes in wireless mobile adhoc networks (MANET) by applying machine learning techniques is an attempt to enhance security by detecting the presence of malicious nodes. MANETs are prone to many security vulnerabilities due to its significant features. The paper compares two machine learning techniques namely Support Vector Machine (SVM) and Back Propagation Neural Network (BPNN) and finds out the best technique to detect the misbehaving nodes. This paper is simulated with an on-demand routing protocol in NS2.35 and the results can be compared using parameters like packet Delivery Ratio (PDR), End-To-End delay, Average Throughput.

The dynamic and adaptable characteristics of mobile ad hoc networks have made it a significant field for deploying various applications in wireless sensor networks. Increasing popularity of the portable devices is the main reason for the development of mobile ad hoc networks. Furthermore, the network does not require a fixed architecture and it is easy to deploy. This type of network is highly vulnerable to cyber-attacks as the nodes communicate with each other through a Wireless medium. The most critical attack in ad hoc network is jellyfish attack. In this research we have proposed a Direct Trust-based Detection Algorithm to detect and prevent jellyfish attack in MANET.