The Master’s thesis report describes the wireless mesh networks functions, characteristics, network management and finally different protocols with security issues and applications. Wireless Networks (WMNs) are replacing wireless Infrastructure networks in many areas because of their lower and higher flexibility. The wireless mesh networks (WMNs) provides network access for both mesh and conventional clients through mesh routers and mesh clients. Communication across the network is formed via the bridge functions. Mesh router also provides the minimal mobility and form the backbone of WMNs. Wireless mesh network has resolved the limitation of ad hoc networks which is ultimately improves the performance of Ad hoc networks. Security is a very important issue which can be resolve through proper management of network. The improvment of 802.11i security has greatly improved the network perfomance and increase the encryption and integrity security capabilities. The key points which are being addressed in this report are security issues and threats and their counter measures. Attacks which can come on diffent layers are being discussed in this survey. Security of wireless mesh network is still under consideration. Wireless mesh network are attracting more attention due to its enhanced features. Wireless mesh network topology technology is being discussed in this report. Then network management of WMNs is explained and in the concluding chapters security issues are discussed. Threats, attacks and challenges of WMNs are discussed in this survey.

Wimax (Worldwide Interoperability for Microwave Access) is a standard of wireless metropolitan area networks (WMAN), designed by IEEE 802.16 standards group. The coverage of Wimax is wide, so it is suited for developing in large networks and provides more steady, high-speed, and secure data transmission for fixed and mobile subscribers. As the result, Wimax is designed for solving last mile problem because of the bandwidth is limit and the expensive building cost in the traditional networks. IEEE 802.16 (Wimax) defines two modes of data communication topology: PMP (Point-to-multipoint) mode and Mesh mode. In Mesh mode, the data can route through another subscriber station (SS), so it not only improves coverage range but also raises the throughput. Although IEEE 802.16 defined a secure sub layer in the MAC (Media Access Control) layer to provide privacy by encrypting connections between base station (BS) and subscriber station (SS), but it still face many security problems. In the mesh mode, it is not like PMP mode that the traffic is only between BS and SS, the traffic sometime will pass through another SS, for this reason, it is prone to bring many problems, such as shared secret key exposing, man-in-the-middle attack, eavesdropping threat¡Ketc. On the relay node (we termed sponsor node here), it also involved more unnecessary loads of encryption and decryption. In this thesis, we focus on the MAC layer , and we propose some schemes to modify the present of PKM and the traffic encryption key used for transmitting data, and we will show that these schemes can achieve better security than previous ones, also achieve efficient in data transmission.

Network security is an important domain in the field of computer engineering. Sensitive information flowing across computer networks is vulnerable to potential threats, therefore it is important to ensure their security. Wireless Mesh Networks (WMNs) are self-organized networks deployed in small proximity which have an wireless ad-hoc mesh topology. While they are cost effective and easy to deploy, they are extremely vulnerable to network intrusions due to no central switch or router. However, they can be secured using cryptographic techniques, firewalls or Demilitarized Zones (DMZs). Intrusion Detection Systems (IDSs) are used as a secondary line-of-defence in computer networks from possible intrusions. This thesis proposes a framework for a Hybrid Intrusion Detection System (HIDS) for WMN. / Graduate

>Magister Scientiae - MSc / This thesis validates that packet aggregation is a viable technique to increase call capacity for Voice over Internet Protocol over wireless mesh networks. Wireless mesh networks are attractive ways to provide voice services to rural communities. Due to the ad-hoc routing nature of mesh networks, packet loss and delay can reduce voice quality. Even on non-mesh networks, voice quality is reduced by high overhead, associated with the transmission of multiple small packets. Packet aggregation techniques are proven to increase VoIP performance and thus can be deployed in wireless mesh networks. Kernel level packet aggregation was initially implemented and tested on a small mesh network of PCs running Linux, and standard baseline vs. aggregation tests were conducted with a realistic voice traffic profile in hop-to-hop mode. Modifications of the kernel were then transferred to either end of a nine node 'mesh potato' network and those tests were conducted with only the end nodes modified to perform aggregation duties. Packet aggregation increased call capacity expectedly, while quality of service was maintained in both instances, and hop-to-hop aggregation outperformed the end-to-end configuration 4:1. However, implementing hop-to-hop in a scalable fashion is prohibitive, due to the extensive kernel level debugging that must be done to achieve the call capacity increase. Therefore, end-to-end call capacity increase is an acceptable compromise for eventual scalable deployment of voice over wireless mesh networks.

Recent advances in Wireless Mesh Networks (WMNs) have overcome the drawbacks of traditional wired networks and wireless ad hoc networks. WMNs will play a leading role in the next generation of networks, and the question of how to provide smooth mobility for WMNs is the driving force behind the research. The inherent characteristics of WMNs, such as relatively static backbones and highly mobile clients, require new handoff management solutions to be designed and implemented. This thesis first presents our research work on handoff management schemes in traditional WMNs. In general, a handoff process includes two parts, the MAC layer handoff and the network layer handoff. For the MAC layer handoff, a self-configured handoff scheme with dynamic adaptation is presented. Before the mobile node starts the probe process, it configures parameters for each channel to optimize the scan process. Moreover, a fast authentication scheme to reduce authentication latency for WiFi-based mesh networks is introduced. A tunnel is introduced to forward data packets between the new access router and the original reliable access router to recover data communication before the complete authentication process is finished. To minimize the network layer handoff latency, a hybrid routing protocol for forwarding packets is proposed: this involves both the link layer routing and the network layer routing. Based on the hybrid routing protocol, both intra-domain and inter-domain handoff management have been designed to support smooth roaming in WMNs. In addition, we extend our work to Vehicular Mesh Networks (VMNs). Considering the characteristics of VMNs, a fast handoff scheme is introduced to reduce handoff latency by using a multi-hop clustering algorithm. Using this scheme, vehicle nodes are divided into different multi-hop clusters according to the relative mobility. Some vehicle nodes are selected as assistant nodes; and these assistant nodes will help the cluster head node to determine the next access router for minimizing handoff latency. Extensive simulation results demonstrate that the proposed scheme can reduce handoff latency significantly.

The last couple of years have seen an explosive growth in smartphone sales. Additionally, the computational power of modern smartphones has been increasing at a high rate. For example, the popular iPhone 4S has a 1 GHz processor with 512 MB of RAM [5]. Other popular smartphones such as the Samsung Galaxy Nexus S also have similar specications. These smartphones are as powerful as desktop computers of the 2005 era, and the tight integration of many dierent hardware chipsets in these mobile devices makes for a unique mobile platform that can be exploited for capabilities other than traditional uses of a phone, such as talk and text [4]. In this work, the concept using smartphones that run the Android operating system for distributed computing over a wireless mesh network is explored. This is also known as wireless distributed computing (WDC). The complexities of WDC on mobile devices are different from traditional distributed computing because of, among other things, the unreliable wireless communications channel and the limited power available to each computing node. This thesis develops the theoretical foundations for WDC. A mathematical model representing the total amount of resources required to distribute a task with WDC is developed. It is shown that given a task that is distributable, under certain conditions, there exists a theoretical minimum amount of resources that can be used in order to perform a task using WDC. Finally, the WDC architecture is developed, an Android App implementation of the WDC architecture is tested, and it is shown in a practical application that using WDC to perform a task provides a performance increase over processing the job locally on the Android OS. / Master of Science

Magister Scientiae - MSc / This thesis presents an analysis of the impact of node mobility on the quality of service for voice over Internet Protocol in wireless mesh networks. Voice traffic was simulated on such a mesh network to analyze the following performance metrics: delay, jitter, packet loss and throughput. Wireless mesh networks present interesting characteristics such as multi-hop routing, node mobility, and variable coverage that can impact on quality of service. A reasonable deployment scenario for a small organizational network, for either urban or rural deployment, is considered with three wireless mesh network scenarios, each with 26 mesh nodes. In the first scenario, all mesh nodes are stationary. In the second scenario, 10 nodes are mobile and 16 nodes are stationary. Finally, in the third scenario, all mesh nodes are mobile. The mesh nodes are simulated to move at a walking speed of 1.3m per second. The results show that node mobility can increase packet loss, delay, and jitter. However, the results also show that wireless mesh networks can provide acceptable quality of service, providing that there is little or no background traffic generated by other applications. In particular, the results demonstrate that jitter across all scenarios remains within humanacceptable tolerances. It is therefore recommended that voice over Internet Protocol implementations on wireless mesh networks with background traffic be supported by quality of service standards; otherwise they can lead to service delivery failures. On the other hand, voice-only esh networks, even with mobile nodes, offer an attractive alternative voice over Internet Protocol platform. / South Africa

With the rapid development of wireless networks, mesh networks are evolving as a new important technology, presenting a high research and commercial interest. Additionally, wireless mesh networks have a wide variety of applications, offering the ability to provide network access in both rural and urban areas with low cost of maintenance. One of the main functionalities of a wireless mesh network is load balancing routing, which is the procedure of finding the best, according to some criteria, routes that data need to follow to transfer from one node to another. Routing is one of the state-of-the-art areas of research because the current algorithms and protocols are not efficient and effective due to the diversity of the characteristics of these networks. In this thesis, two new routing algorithms have been developed for No Intra-Cell Interference (NICI) and Limited Intra-Cell Interference (LICI) networks based on WiMAX, the most advanced wireless technology ready for deployment. The algorithms created are based on the classical Dijkstra and Ford-Fulkerson algorithms and can be implemented in the cases of unicast and multicast transmission respectively.

<p>Voice over IP (VoIP) traffic in a multi-hop wireless mesh network (WMN) suffers from a large overhead due to mac/IP/UDP/RTP headers and time collisions. A consequence of the large overhead is that only a small number of concurrent VoIP calls can be supported in a WMN[17]. Hop-to-hop packet aggregation can reduce network overhead and increase the capacity. Packet aggregation is a concept which combines several small packets, destined to a common next-hop destination, to one large packet. The goal of this thesis was to implement packet aggregation on a Linux distribution and to increase the number of concurrent VoIP calls. We use as testbed a two-hop WMN with a fixed data rate of 2Mbit/s. Traffic was generated between nodes using MGEN[20] to simulate VoIP behavior. The results from the tests show that the number of supported concurrent flows in the testbed is increased by 135% compared to unaggregated traffic.</p>

<p>Wireless mesh networks has rapid development over the last few years. However, due to properties such as distributed infrastructure and interference, which strongly affect the performance of wireless mesh networks, developing technology has to face the challenge of architecture and protocol design issues. Traditional layered protocols do not function efficiently in multi-hop wireless environments. To get deeper understanding on interaction of the layered protocols and optimize the performance of wireless mesh network, more recent researches are focusing on cross-layer measurement schemes and cross-layer protocol design. The goal of this project is to implement a distributed monitoring mechanism for IEEE802.11 based wireless mesh networks. This module is event-based and has modular structure that makes it flexible to be extended. This project results a novel Cross-Layer Monitoring Module, CLMM, which is a prototype that monitors each layer of the nodes locally and dynamically, calculates the average values of the metrics, compares these values with thresholds and handles the cross-layer messages of each node. The CLMM also has a routing module structure that can be extended to distribute the metrics to its neighbors.</p>