Co-operation Enforcing Reputation-Based Detection Techniques and Frameworks for Handling Selfish Node Behaviour in MANETs: A Review

Exponential reliability factor based mitigation mechanism for selfish nodes in MANETs

In mobile ad hoc networks (MANETs), network survivability is considered as a potential factor required for maintaining maximum degree of connectivity among the mobile nodes even during failures and attacks. But, the selfish mobile nodes pose devastating influence towards network survivability. Hence, a prediction model that assesses network survivability through stochastic properties derived from nodes’ behaviour becomes essential. This paper proposes a futuristic trust coefficient-based semi-Markov prediction model (FTCSPM) that investigates and quantifies the impact of selfish behaviour towards the survivability of the network. This FTCSPM approach incorporates a non birth-death process for manipulating futuristic trust coefficient since it does not consider the transition of a mobile node from the failed state to a selfish state into account. This semi-Markov prediction model also aids in framing a lower and upper bound for network survivability. Extensive simulations were carried out through ns-2 and the results indicates that FTCSPM show better performance than the existing benchmark mitigation mechanisms like correlated node behaviour model (CNBM), probabilistic behavior model (PBM) and epidemic correlated node behavioural model (ECNBM) proposed for selfish nodes. Further, FTCSPM isolates the selfish nodes rapidly at the rate of 33 % than the considered benchmark systems. Furthermore, the validation of this prediction model performed through Weibull distribution has a high degree of correlation with the simulation results and thus assures the reliability and correctness of the proposed approach. In addition, this approach computes the mean transition time incurred by a mobile node to transit from cooperative to selfish mode as 6.49 s and also identifies the minimum and maximum selfish behaviour detection time as 140 and 180 s, respectively.

The applications and protocols conceived for mobile ad hoc networks rely on the assumption of cooperation amongst the mobile nodes because of lacking infrastructure. All nodes have to spend their precious resources (e.g. battery power, memory, computational power, and network bandwidth) for routing and packet forwarding operations for other nodes, in a cooperative way in the network. However, there are some nodes that may intentionally turn themselves to behave selfishly in order to conserve their valuable resources. The selfish behaviour of such nodes drastically reduces the desired degree of cooperation amongst the mobile nodes. Over the course of time, the non-cooperative activities of, such selfish nodes would paralyze the normal functioning of the whole network. Therefore, these types of nodes should be detected and isolated from the network, as soon as they begin to exhibit their selfish behaviour. In this paper, a dynamic trust based intrusion detection technique is presented to detect and isolate the selfish nodes from the network, where the direct trust degree based on direct communication interactions and indirect (recommended) trust degree based on the neighbours’ recommendations are taking into account to accurately judge the selfishness nature of the nodes. The results obtained throughout the simulation experiments clearly show the feasibility and effectiveness of the proposed intrusion detection technique.

Impact of node distance on selfish replica allocation in a mobile ad-hoc network

A mobile ad-hoc network is an autonomous system having collection of mobile nodes connected by wireless links. Mobile nodes in a MANET communicate with each other based on unconditional cooperation and inherited trustworthiness. MANET is vulnerable due to the characteristics such as dynamic topology and openness. This leads to the exploitation of MANET by performing various kinds of attacks by the presence of malicious and (or) selfish nodes. Such nodes affect the normal routing process in a MANET thereby impacting the routing performances such as packet delivery ratio. Hence, the necessity of trust factor between communication nodes is substantiated. In this paper the proposed solution identifies the malicious and selfish behaviour of nodes by dynamic calculation of trust and energy values of the nodes in the topology. The proposed algorithm, Trust and Energy based Ad hoc On Demand Distance Vector improves the traditional AODV algorithm by the dynamic incorporation of trust and energy values for each node in the topology in order to achieve cooperative routing. In Trust and Energy based Ad hoc On Demand Distance Vector, the source node selects the cooperative path rather than the shortest path thereby isolating the malicious and selfish nodes. Finally, the simulation results show that the proposed Trust and Energy based Ad hoc On Demand Distance Vector routing algorithm isolate the malicious and selfish nodes, and substantially improves the routing performance such as packet delivery ratio and average end to end latency.

The degree of packet dissemination among the mobile nodes of the network depends on the reliability of each individual mobile node attributed towards the benefits of the other interacting nodes in forwarding activity. However, the selfish intent of selfish nodes in the network reduces the performance in terms of packet forwarding rate. Thus, the influence of selfish intent in the network need to be minimized to the maximum level by introducing a predominant isolation process. In this paper, a Gwet Kappa Reliability Factor-based Selfish Node Detection Technique (GKRF-SNDT) scheme is proposed for superior detection of selfish nodes in the network. This proposed GKRF-SNDT scheme inherently derives the advantages of Gwet Kappa Reliability Factor for quantifying the degree of trust possessed by each mobile nodes interacting in the network. The experimental investigations of the proposed GKRF-SNDT scheme confirmed a superior throughput rate of 18% with reduced energy consumptions of 21% compared to the existing selfish intent isolation approaches.

A mobile ad hoc network (MANET) is a group of nodes constituting a network of mobile nodes without predefined and pre-established architecture where mobile nodes can communicate without any dedicated access points or base stations. In MANETs, a node may act as a host as well as a router. Nodes in the network can send and receive packets through intermediate nodes. However, the existence of malicious and selfish nodes in MANETs severely degrades network performance. The identification of such nodes in the network and their isolation from the network is a challenging problem. Therefore, in this paper, a simple reputation-based scheme is proposed which uses the consumption and contribution information for selfish node detection and cooperation enforcement. Nodes failing to cooperate are detached from the network to save resources of other nodes with good reputation. The simulation results show that our proposed scheme outperforms the benchmark scheme in terms of NRL (normalized routing load), PDF (packet delivery fraction), and packet drop in the presence of malicious and selfish attacks. Furthermore, our scheme identifies the selfish nodes quickly and accurately as compared to the benchmark scheme.

Ad hoc networks are usually made of selfish mobile nodes which act to meet the benefit of themselves. A mass of researches have carried out to overcome the problems in these selfish networks, including packet forwarding. A class of reputation based schemes has been proposed for the problem, but almost all of them ignore the incentive compatibility of punishment. Punishing a noncooperative actor always costs the punisher a number of resources, which can cause second-ordered free riding that selfish nodes should free ride the punisher by acting cooperatively unconditionally and avoid the cost of punishment. The paper discusses this problem for packet forwarding in ad hoc networks and proposes two solutions based on second-ordered reputation, one is called probabilistic service assignment rule and the other is called proportional assignment rule. When network load is high, only the first one is effective.

In Mobile Ad-hoc Networks (MANETs), each node is free to move and connect with one another over a wireless connection, without the requirement for a centralized controller or base station. These features make MANET useful and functional in a variety of areas, including tactical situations, sensor networks, rescue operations, and students on campus. However, this type of network also has a range of issues such as security, Quality of Service, dynamic topology, scalability, the absence of central management, and energy consumption. Since MANET nodes have little battery life, the power usage is among the most important design considerations in wireless ad-hoc networks. Each node is responsible for forwarding the packets to its neighboring nodes. Since the MANET does not contain a hierarchy, some nodes may not participate in forwarding the packets and prefer to keep their remaining energy for themselves; these nodes are called selfish nodes. The presence of selfish nodes in the MANET greatly affects the efficiency and activity of the network. The process of detecting and isolating the selfish node does not constitute an easy task. It still requires further investigation and study. Therefore, this survey is intended to determine, study and analyze some new detection mechanisms used in detecting selfish nodes in MANETs. It also classifies them into three categories which are credit-based, reputation-based, and acknowledgment-based techniques. In addition, it highlights some critical issues in MANET according to selfish behavior, and points out the necessary requirements for better improvement as well as fields for future research.

In MANETs, the mobile nodes usually relay other nodes’ packets for the proper operation of the network. However, selfish nodes usually don’t cooperate in relaying other nodes’ packets but use the regular nodes to relay their packets. The increase in the number of selfish nodes affects the network performance badly. Existing protocols try to minimize the impact of selfish nodes with high computation overhead and/or communication overhead. In this paper, triple referee incentive mechanism is proposed that employs three referees to monitor the behavior of any intermediate node. In case of any selfish behavior, the packets will be bypassed through the referee nodes so that the data communication is uninterrupted in the network. In addition, the selfish nodes are motivated through incentives with less packet overhead. Hash operations are used in the data packets and acknowledgement packets instead of the public key cryptography operations so that the average packet overhead is less than that of the public key cryptography based incentive protocols. Hash values are used to attain payment non repudiation and restrain free riding attacks.

Intrusion Detections Systems(IDSs) in ad hoc net- works monitor other devices for intentional deviation from protocol, i.e., misbehavior. This process is complicated due to limited radio range and mobility of nodes. Unlike conventional IDSs, it is not possible to monitor nodes for long durations. As a result IDSs suffer from a large number of false positives. Moreover other environmental conditions like radio interference and congestion increase false positives, complicating classification of legitimate nodes and attackers. We present a scheme that helps in accurate diagnosis of malicious attacks in ad hoc networks. Our scheme employs cross- layer interactions based on observations at various networking layers to decrease the number of false positives. Our simulations show that our scheme is more effective and accurate than those based on isolated observations from any single layer. I. INTRODUCTION Mobile ad hoc networks (MANETs) are comprised of a dy- namic set of cooperating peers, which share their wireless ca- pabilities with other similar devices to enable communication with devices not in direct radio-range of each other, effectively relaying messages on behalf of others. Conventional methods of identification and authentication are not available, since the availability of a Certificate Authority (CA) or a Key Distribu- tion Centre (KDC) cannot be assumed. Consequently, mobile device identities or their intentions cannot be predetermined or verified. Communication protocols are though designed for fairness in contention resolution provide no enforcement mechanism to ensure it. Protocols are fair to the extent to which the de- vices conform to the protocol specifications. Wireless Medium Access Control(MAC) Protocols like 802.11 that employ dis- tributed contention resolution for gaining access to the shared wireless channel are susceptible to attack from selfish nodes trying to gain an unfair share of the medium. The various networking layers from the lowest physical layer to the application layer were designed for with the tacit assumption that devices comprising the network will be protocol conformant. Herein lie several security threats, some arising from short- comings in the protocols, and others from the lack of con- ventional identification and authentication mechanisms. These inherent properties of ad hoc networks make them vulnerable, and malicious nodes can exploit these vulnerabilities in the networking layers for selfish or even malicious motives. Selfish nodes can slightly deviate from the MAC protocol specifi- cation for contention resolution in order to gain an unfairly large share of the bandwidth. More harmful attacks like packet dropping, routing disruption, jamming attacks or other forms of Denial-of-Service (DOS) at any of the networking layers can severely disrupt MANET communications. Traditionally, intrusion detection involves looking at events and activities in individual layers of the modeled OSI stack. Various pattern matches at the Transport layer, for example, can indicate SYN attacks. However, sophisticated attacks that simultaneously exploit vulnerabilities at multiple layers of the communication proto- cols will be especially hard to detect. By using observations of both external and internal events at multiple layers of the OSI our approach will be to use observations both external and internal from various layers of the OSI stack for a more accurate evaluation of bad nodes and good nodes. In this paper we show the results of looking specifically at malicious RTS activity in the 802.11 MAC layer when combined with packet dropping at the Network layer. Robust IDS and response systems will depend on accurate classification of attacks and identification of attackers. In order for devices to establish and maintain trust relations - and evolve reputations, there is a need to balance the intrusion de- tection effort with the individual node's primary function. The goal is to maximize the probability that malicious behavior will be correctly detected (True Positives), while minimizing the probability that good nodes will be falsely accused (False Positives).

Mobile Ad-Hoc Networks (MANETs) face many quality of service challenges including bandwidth, utilization, and end-to-end delay. This paper aims to provide a solution for improving the average delays between end-to-end devices while taking into consideration the arrival process, collision avoidance, and back-off mechanisms. The primary purpose is to accurately deliver the packets from one end to another while selfish nodes are manipulated or ignored during the packets delivery. A node is selfish if it is not forwarding the packets to its neighbor nodes to preserve its resources. The detection of the selfish nodes and the malicious attackers is done using watchdogs where the selfish nodes are divided into 3-degree levels. Using this mechanism, we identify the threshold of the node to identify normal nodes, selfish nodes that are allowed to transmit, and selfish nodes that are prevented transmission. In this paper we suggest a new algorithm to mitigate selfish nodes, to simulate the proposed algorithm, and to evaluate its performance against other mechanisms presented in the literature.

A network connecting mobile nodes wirelessly is known as mobile ad-hoc network (MANET). In MANET the communication takes place with the help of mobile nodes. Every node in a MANET forwards data so that it can reach to its destination. It is assumed that all the nodes in the network behave properly while forwarding the data packets. Selfish nodes are those nodes who do not participate in data forwarding. The presence of such selfish nodes degrade the performance of MANET. In this paper, we survey the various mechanisms to detect selfish node in MANET.

Data replication is performed in mobile ad hoc networks (MANET) to improve data availability in presence of network partition due to high mobility rate of nodes. Replication helps to improve data availability by making multiple copies of same data on several nodes. Various techniques have been proposed in the literature for data replication in MANET. Since mobile nodes are characterized by limited memory space, computing capacity, constrained bandwidth and limited battery power, they extend less or no cooperation in participating replica allocation. Several approaches have been proposed in the literature to handle selfishness among nodes in replica allocation. But the proposed approaches consist of several modules to identify selfish nodes, elimination of selfish nodes, updating selfish features and finding the non selfish nodes to allocate a data replica. Existing replica allocation algorithms achieves better performance in allocating replica, but it consumes more time to allocate replica and the number of messages transmitted in the network during replica allocation. We propose a light weight replica allocation algorithm with reduced replica allocation time and reduced number of messages involved during replica allocation. We have analyzed the existing algorithm for replication in MANET and presented optimizations in the steps involved so that the overall replica allocation time and the messages involved are reduced to a large extent. We suggest the usage of Fisheye state routing protocol along with the replication algorithm that finds the hop count by which a node is connected from the other node. We have formulated a mathematical model to illustrate the benefits of the proposed approach and performed a simulation in MATLAB. The results obtained show a significant reduction in replica allocation time and the amount of messages involved in performing replica allocation compared to the existing algorithms.

Modern Wireless Local Area Networks (WLANs) with relatively high data rates have become an attractive technology for providing Internet connectivity for mobile users. Ad-hoc networks are a collection of mobile nodes that can be deployed without the need for any centralized management infrastructure. In such a set-up, to establish the required communication paths, each node must be willing to act as a potential router. In practice though, some nodes may act selfishly and refuse to forward packets. In Ad-hoc networks, a node may be considered as misbehaving for different reasons, for instance when it acts selfishly, refusing to forward packets. In some circumstances, the node can be overloaded, or they simply want to save their resources by not forwarding packets unless they are of direct interest to the node itself. Conversely, these nodes may still be expecting others to forward packets on their behalf. In this paper, we report the experimental results obtained from a typical Ad-hoc networks that contain selfish nodes. We also analyze the behavior of the nodes, to establish some quantifiable measure of their reliability. Such measures, based on the behavior history of the nodes, are then utilized to improve the performance and reliability of the widely used Ad-hoc On Demand Distance Vector routing protocol. We also report the results of simulations of large Ad-hoc networks in the presence of malicious or selfish nodes. These results clearly indicate the capabilities of the proposed approach in discovering communication paths with a minimal number of malicious or selfish nodes.