Biblio

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.

Mobile Adhoc Network (MANET) are the networks where network nodes uses wireless links to transfer information from one node to another without making use of existing infrastructure. There is no node in the network to control and coordinate establishment of connections between the network nodes. Hence the network nodes performs dual function of both node as well as router. Due to dynamically changing network scenarios, absence of centralization and lack of resources, MANETs have a threat of large number of security attacks. Hence security attacks need to be evaluated in order to find effective methods to avoid or remove them. In this paper malicious behavior of Blackhole attack and Rushing attack is studied and analyzed for QoS metrics.

Mobile adhoc network are fully autonomous where the nodes act both as node as well as router. Centralization is absent in MANETs. In MANETs nodes are continuously moving and have an open access which put it at a risk of large number of attacks. Security in such networks is therefore a critical matter. In order to find solution to this issue various attacks need to be studied and analyzed. In Blackhole attack, the unauthorized node in the path of source and target nodes takes away the packets sent by the source and drops them by not heading them towards the target node. The malicious behavior launched by Blackhole attack deteriorates the network performance.

Vehicular ad hoc networks (VANETs) are eminent type of Mobile ad hoc Networks. The network created in VANETs is quite prone to security problem. In this work, a new mechanism is proposed to study the security of VANETs against DDoS attack. The proposed mechanism focuses on distributed denial of service attacks. The main idea of the paper is to detect the DDoS attack and mitigate it. The work consists of two stages, initially attack topology and network congestion is created. The second stage is to detect and mitigate the DDoS attack. The existing method is compared with the proposed method for mitigating DDoS attacks in VANETs. The existing solutions presented by the various researchers are also compared and analyzed. The solution for such kind of problem is provided which is used to detect and mitigate DDoS attack by using greedy approach. The network environment is created using NS-2. The results of simulation represent that the proposed approach is better in the terms of network packet loss, routing overhead and network throughput.

The underlying element that supports the device communication in the MANET is the wireless connection capability. Each node has the ability to communicate with other nodes via the creation of routing path. However, due to the fact that nodes in MANET are autonomous and the routing paths created are only based on current condition of the network, some of the paths are extremely instable. In light of these shortcomings, many research works emphasizes on the improvement of routing path algorithm. Regardless of the application the MANET can support, the MANET possesses unique characteristics, which enables mobile nodes to form dynamic communication irrespective the availability of a fixed network. However the inherent nature of MANET has led to nodes in MANET to be vulnerable to denied services. A typical Denial of Service (DoS) in MANET is the Black Hole attack, caused by a malicious node, or a set of nodes advertising false routing updates. Typically, the malicious nodes are difficult to be detected. Each node is equipped with a particular type of routing protocol and voluntarily participates in relaying the packets. However, some nodes may not be genuine and has been tampered to behave maliciously, which causes the Black Hole attack. Several on demand routing protocol e.g. Ad hoc On Demand Distance Vector (AODV) and Dynamic Source Routing (DSR) are susceptible to such attack. In principle, the attack exploits the Route Request (RREQ) discovery operation and falsifies the sequence number and the shortest path information. The malicious nodes are able to utilize the loophole in the RREQ discovery process due to the absence of validation process. As a result, genuine RREQ packets are exploited and erroneously relayed to a false node(s). This paper highlights the effect Black Hole nodes to the network performance and therefore substantiates the previous work done [1]. In this paper, several simulation experiments are iterated using NS-2, which employed various scenarios and traffic loads. The simulation results show the presence of Black Hole nodes in a network can substantially affects the packet delivery ratio and throughput by as much as 100%.