Quality of Service (QoS) in Ad hoc networks (MANETs) and more precisely in routing is the subject of several studies with the aim of providing better solutions for new applications requiring high throughput and very low delay.
The objective of this work is to enhance the AODV (Ad hoc On Demand Distance Vector) routing strategy in maintenance phase, to improve QoS. It aims to add a mechanism able to predict link failure in use based on signal strength which is able to determine if the quality of link will be improved (i.e. stable) or more bad (i.e. probability of failure) in order to allow us not only to make the link management more robust but to anticipate on link breaking and improve QoS. When signal quality is declining due to neighbor node remoteness, a discovery of a part of road rescue with two hops will be established and it will be used when disconnection happens. Simulations under Network Simulator (Ns2) were conducted to measure traffic control, packets delivery and lost ratio in original protocol and modified version which are presented in this paper.

ZigBee is a low cost, low-power consumption and long battery life network that is based on the IEEE 802.15.4 standard; which is most usually used to transfer low data rates information in the Wireless Personal Area Network (WPAN). In the Wireless Personal Area Network (WPAN) network, capability of sensor network and mobile network are combined that have energy limit and sensing range limits. Here a network is composed of a number of Sub-Network or groups with the selection of group leader. Group formation is defined under sensing range limit, density limit and type of nodes. The selection of group leader is defined under velocity analysis, energy and average distance after that inter group and intra group communication is performed and then Handoff mechanism is performed when nodes switch the group or group switch the base station.

Optical packet switching is one of promising technology for the next generation high speed data transfer. In OPS contention among the packets is a major problem, to counteract the problem deflection and buffering of contending packets is proposed. In this paper, a six node network is considered and usability of both deflection routing and buffering of packets is discussed. The results are obtained through simulations, in terms of packet loss probability and average delay. This has been found that in general buffering of contending packets is better option in comparison to deflection. However, in case of load balancing, deflection routing is desirable as some packets take alternative routes to reach its destination. Load balancing scheme reduces the packet loss rate at contending node but it increases the total delay.

The image security on internet transfers is the concern of the hour as the breaching attacks into the image databases are rising every year. The hackers take advantage of the stolen personal and important images to fulfill their dangerous and unethical intentions. The image data theft can be used to defame a person on the internet by posting the illegal and unacceptable images of that person (internet user). Hence the images transfers have to be secure to ensure the privacy of the user’s image data. In this research, a number of image security systems have been studied to evaluate the research gap. Majority of the existing image security systems are not up to date to protect against the latest breaching attacks. So, we have proposed an effective and robust image security framework particularly designed for the images. The proposed has been designed and implemented using MATLAB. In this research, a hybrid image security framework has been proposed to overcome the problem stated earlier, which will be implemented by combining various techniques together to achieve the image security goal. The techniques included in the combination would beimage compression, cryptography and steganography. DWT compression has been used, because it is a stronger compression algorithm. The steganographed image would be compressed to reduce its size. Blowfish encryption algorithm would be used for the encryption purposes. It offers maximum throughput (faster) and also energy efficient. Compressed image would be encrypted to enhance the image security. Real image will be hidden into another image. A cluster based steganographic technique will be used. Real image and face image would be analyzed, and the real image would be embedded in those areas of face image, where color schemes of the real image and face image would be most similar. Kmeans or Hierarchical clustering would be used as a clustering technique. An all new comparative analysis technique would be applied to make the comparison between real image and base image on the basis of color patterns.

In recent years, the area of formal verification of cryptographic protocols became important because of the active intruders. These intruders can find out the flaws in the protocols and can use them to create attacks. To avoid such possible attacks, the protocols must be verified to check if the protocols contain any flaws. The formal verification tools have helped in verifying and correcting the protocols. Various tools are available these days for verifying the protocols. In this paper, the two verification tools namely ProVerif and AVISPA are used for analysis of protocols - AKI (Accountable Key Infrastructure), ARPKI (Attack Resilient Public Key Infrastructure) and OPT (Origin and Path Trace). A comparative evaluation of the selected tools is presented and revealed security properties of the protocols selected.

In mobile ad hoc networks (MANETs), high node mobility leads to frequent link breaks and creates complexities in route discovery, this effect on the quality of service (QoS) and degrades the systems performance. So, providing a high quality communication using stable links among mobile nodes is a challenging issue in MANETs. Existing stability based routing algorithms initiate estimation of route stability metrics during the routing process, results in increased delay and overhead. In order to overcome these issues, in this paper, we construct a stable backbone-based multipath routing protocol (SBMRP). Initially, the nodes with high residual bandwidth, residual power, link quality and low mobility are designated as candidate nodes. Then multiple paths are established between source and destination through these candidate nodes, thus forming a routing backbone. If any candidate node in the path tend to fail due to lack of bandwidth, energy or link quality, alternate path through other candidate node is established before path breaks. Proposed routing scheme has been compared with other three existing protocols: AODV, AOMDV and RSQR. The protocol performance has been evaluated in terms of packet delivery ratio, normalized routing load, delay and packet drop ratio.

In Mobile Ad hoc Network, path between source and destination node changes too frequently due to unpredictable behavior and movement of mobile nodes. The data delivery to the intended destination becomes very challenging. The paths exist between source and destination node may be various types. Data delivery may be done with single or multiple paths. Single path sometimes not guaranteed about data delivery, so one of the better solution is multipath data delivery. Here, in this paper, we have considered Link Disjoint and Node Disjoint multipath for data delivery. For this AOMDV protocol with node and link disjoint is considered to evaluate performance. To evaluate their performance different node pause time considered with varying number of nodes. We have computed various QoS network metrics like throughput, average end-to-end delay, routing overhead to identify in which method of data delivery perform better and in what conditions.  The results obtain shows that Node Disjoint multipath method AOMDV performs better than Link Disjoint method. The simulation work carried out using Simulator NS-2.34.

Cognitive Radio has been considered a key technology in the future wireless communication. These radio networks with their spectrum sensing capability have become one of the most reliable wireless communication networks. Basically, these networks employ two types of users PU’s (Primary Users) having licensed frequency band for their usage and SU’s (Secondary Users) that can intelligently detect which communication channels are available and move into vacant ones while avoiding occupied ones. To have communication among these users, a routing protocol is used whose basic purpose is to provide a reliable route from source to destination. An important parameter while designing a routing strategy is the consideration of overall throughput of path. In this paper we consider the same to find the most optimal throughput path using fuzzy logic theory. MATLAB-7.01 is used for implementation and results show that our proposed scheme outperforms shortest spectrum aware routing scheme.