With the main focus of research in routing protocols for Mobile Ad-Hoc Networks (MANET) geared towards routing efficiency, the resulting protocols tend to be vulnerable to various attacks. Over the years, emphasis has also been placed on improving the security of these networks. Different solutions have been proposed for different types of attacks, however, these solutions often compromise routing efficiency or network overload. One major DOS attack against the Optimized Link State Routing protocol (OLSR) known as the node isolation attack occurs when topological knowledge of the network is exploited by an attacker who is able to isolate the victim from the rest of the network and subsequently deny communication services to the victim. In this paper, we suggest a novel solution to defend the OLSR protocol from node isolation attack by employing the same tactics used by the attack itself. Through extensive experimentation, we demonstrate that 1) the proposed protection prevents more than 95 percent of attacks, and 2) the overhead required drastically decreases as the network size increases until it is non-discernable. Last, we suggest that this type of solution can be extended to other similar DOS attacks on OLSR.

Wireless sensor networks (WSN) are susceptible to various kinds of attack, and node replication attack is one of them. It is considered to be one of the most serious attacks in WSN. In this type of attack, an adversary deploys clones of a legitimate node. These clones participate in all network activities and behave identically same as the legitimate node. Therefore, detection of clones in the network is a challenging task. Most of the work reported in the literature for clone detection is location dependent. In this paper, we have proposed a location independent zone-based node replica detection technique. In the proposed scheme, the network is dynamically divided into a number of zones. Each zone has a zone-leader, and they share their membership list among themselves. It is the responsibility of the zoneleader to detect the clone. The proposed technique is a deterministic one.We have compared our scheme with LSM, RED, and P-MPC and observed that it has a higher clone detection probability and a lower communication cost.

The accuracy of wireless network packet simulation critically depends on the quality of wireless channel models. Path loss is the stationary component of the channel model affected by the shadowing in the environment. Existing path loss models are inaccurate, require excessive measurement or computational overhead, and/or often cannot be made to represent a given environment. This paper contributes a flexible path loss model that uses a novel approach for spatially coherent interpolation from available nearby channels to allow accurate and efficient modeling of path loss. We show that the proposed model, called Double Regression (DR), generates a correlated space, allowing both the sender and the receiver to move without abrupt change in path loss. Combining DR with a traditional temporal fading model, such as Rayleigh fading, provides an accurate and efficient channel model that we integrate with the NS-2 simulator. We use measurements to validate the accuracy of the model for a number of scenarios. We also show that there is substantial impact on simulation behavior when path loss is modeled accurately. Finally, we show that unlike statistical models, DR can make a simulation representative of a given environment by using a small number of seeding measurements. Thus, DR provides a cost-effective
alternative to ray tracing or detailed site surveys.