Supporting Internet Access and Quality of Service in Distributed Wireless Ad Hoc Networks

In this era of wireless hysteria, with continuous technological advances in wireless communication and new wireless technologies becoming standardized at a fast rate, we can expect an increased interest for wireless networks, such as ad hoc and mesh networks. These networks operate in a distributed manner, independent of any centralized device. In order to realize the practical benefits of ad hoc networks, two challenges (among others) need to be considered: distributed QoS guarantees and multi-hop Internet access. In this thesis we present conceivable solutions to both of these problems. An autonomous, stand-alone ad hoc network is useful in many cases, such as search and rescue operations and meetings where participants wish to quickly share information. However, an ad hoc network connected to the Internet is even more desirable. This is because Internet plays an important role in the daily life of many people by offering a broad range of services. In this thesis we present AODV+, which is our solution to achieve this network interconnection between a wireless ad hoc network and the wired Internet. Providing QoS in distributed wireless networks is another challenging, but yet important, task mainly because there is no central device controlling the medium access. In this thesis we propose EDCA with Resource Reservation (EDCA/RR), which is a fully distributed MAC scheme that provides QoS guarantees by allowing applications with strict QoS requirements to reserve transmission time for contention-free medium access. Our scheme is compatible with existing standards and provides both parameterized and prioritized QoS. In addition, we present the Distributed Deterministic Channel Access (DDCA) scheme, which is a multi-hop extension of EDCA/RR and can be used in wireless mesh networks. Finally, we have complemented our simulation studies with real-world ad hoc and mesh network experiments. With the experience from these experiments, we obtained a clear insight into the limitations of wireless channels. We could conclude that a wise design of the network architecture that limits the number of consecutive wireless hops may result in a wireless mesh network that is able to satisfy users’ needs. Moreover, by using QoS mechanisms like EDCA/RR or DDCA we are able to provide different priorities to traffic flows and reserve resources for the most time-critical applications

Performance comparison between Ad Hoc On Demand Distance Vector and Dynamic Source Routing Protocols with security encryption using OPNET

Application for wireless networking has been evolving rapidly and is becoming an integral part in our everyday life. Also with the recent performance advancement in wireless communication technologies, mobile wireless ad-hoc networks has been used in many areas such as military, health and commercial applications. Mobile ad hoc networks utilize radio waves and microwaves to maintain communication channel between computers. 802.11 (Wi-Fi) is the pre-eminent technology for building general purpose wireless networks. Mobile ad-hoc networking (MANET) utilize the Internet Protocol (IP) suite and aims at supporting robust and efficient operation by incorporating routing functionality into the mobile nodes. MANET is among one of the wireless networks that uses 802.11 to transmit data from the source to the destination. Since MANET is used in applications like defense, security is of vital importance due to its wireless nature. Wireless networks are vulnerable to attacks like eavesdropping, Man-In-The-Middle-Attack (MITM), hijacking, and so are MANETs. A malicious node can get within the wireless range of the nodes in the MANET and can disrupt the communication process. Various routing protocols have been proposed using encryption techniques to protect routing in MANETs. In this thesis, I implemented security encryption techniques (SHA-1 and RSA)in two reactive routing protocols which are Ad Hoc On Demand Distance Vector (AODV) routing protocol and Dynamic Source Routing (DSR) routing protocol and compared their network performance using performance evaluation parameters: Average end-to-end-delay, routing load, packet delivery fraction. Encryption techniques like SHA-1 and RSA were used to maintain the confidentiality and the integrity of the messages send by the nodes in the network. There have been several researches so for but no one has ever compared the performance of secured MANET protocols. I am going one step further by comparing the secured routing protocols which would be helpful in determining which protocol performs better that can be used in scenario where security is of utmost importance

A Performance Analysis of the Optimized Link State Routing Protocol Using Voice Traffic Over Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) have grown in popularity over the past decade and are increasingly considered for time-sensitive multimedia applications. The impact of various routing protocols on voice traffic using different IEEE 802.11 extensions has been investigated via analytical models, simulations and experimental test beds. Many studies determined that optimized link state routing (OLSR) is a suitable routing protocol to support voice over internet protocol (VoIP) conversations. This research expands upon this understanding by determining the point at which voice traffic is no longer feasible in an ad hoc environment and determines which audio codec is best suited for MANETS. The MANET simulation environment is established using OPNET. Varying combinations of workloads are submitted to the MANET to capture voice performance within a stressed environment. Performance metrics are compared against established benchmarks to determine if thresholds for unacceptable voice quality are exceeded. Performance analysis reveals that VoIP communication using G.711 is not sustainable at walking (1.5 m/s) or jogging (2.5 m/s) speeds when three simultaneous streams are used. Also, G.729a is determined to be the best suited codec for MANETs since it significantly outperforms the other codecs in terms of packet loss and end-to-end delay

Video streaming over Ad hoc on-demand distance vector routing protocol

Video streaming is content sent in compressed form over the netwoks and viwed the users progressively. The transmission of video with the end goal that it can be prepared as consistent and nonstop stream. The point is that to give client support to client at anyplace and at whatever time. Mobile Ad hoc Networks (MANETs) are considered an attractive nertwork for information transmission in many applications where the customer programme can begin showing the information before the whole record has been transmitted. Ad hoc On-demand Distance Vector (AODV) protocol is considered as one of the most important routing protocols in MANET. However, routing protocols assume a crucial part in transmission of information over the network. This paper investigates the performance of AODV Routing Protocol under video traffic over PHY IEEE 802.11g. The protocol model was developed in OPNET. Different outcomes from simulation based models are analyzed and appropriate reasons are also discussed. A different scenarios of video streaming were used. The metric in terms of throughput, end to end delay, packet delivery ratio and routing overhead were measured. A comparision with GRP and GRP are also reported

Performance study of Hybrid Wireless Mesh Protocol(HWMP) for IEEE 802.11s WLAN Mesh Networks

Wireless Mesh Network (WMN) have been envisioned as an important solution to the next generation wireless networking which can be used in wireless community networks, wireless enterprise networks, transportation systems, home networking and last-mile wireless internet access. Many proprietary mesh solutions were developed by individual vendor but in order to interoperability; IEEE forms a task group called IEEE 802.11s to develop an integrated mesh networking solution. Hybrid Wireless Mesh protocol (HWMP) and airtime metrics as default routing protocol and routing metrics set by the task group. There is few test bed and many simulation studies have been done to evaluate the performance of the HWMP protocol with the assumption of unique type of flow with fixed packet size and packet rate. However, real networks carry a diverse application (video, voice, FTP, Email etc) with different characteristics (packet size, data rate). In this paper, we are investigated and analyzed the performance of HWMP protocol under such heterogeneous application characteristics

Improving the Performance of Wireless LANs

This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids

Performance Evaluation of Routing Metrics for Community Wireless Mesh Networks

With the growth of different types of Internet traffic there is a compelling need to provide better quality of service, especially, over the increasing number of wireless networks. Expected Transmission Count (ETX) is a high throughput route selection metric that measures link loss ratios. ETX of a path reflects the total number of packet transmissions (including retransmission) required to successfully deliver a data packet along that path. Expected Transmission Time (ETT) is an improvement of ETX. ETT of a path is a measure of the transmission time needed to successfully deliver a packet along the path. ETT measures the loss ratio and the bandwidth of the link. Both, ETX and ETT, in comparison to hop count, provide better route selection for routing protocols widely used in Wireless Mesh Networks (WMNs). Using minimum hop count to find the shortest path has been shown to be inadequate for WMNs, as the selected routes often include the weakest links. This thesis presents a performance evaluation comparing hop count, ETX and ETT when used with the Optimized Link State Routing version 2 (OLSRv2) protocol. This study is based on the wireless mesh topology of a suburban residential area in New Zealand, and analyses the performance of three common Internet traffic types in terms of throughput, end-to-end delay, jitter and packet loss ratio, and presents findings that are closer to the perspective of what an enduser experiences. Also, a grid network of 121 nodes was used to analyze how the metrics choose paths, the performance changes (for different path lengths) and other conditions that affect the performance of the three metrics

Design and Implementation of ID Based MANET Autoconfiguration Protocol

Auto-configuration protocols are used for assignment of unique IP addresses to nodes in Mobile ad hoc networks. Without the assignment of unique IP addresses, service provisioning between the nodes is not possible. Such protocols use various heuristics to ensure the uniqueness in IP address assignment; such aspects increase the overall complexity in MANET system design. Moreover the overriding role of IP address as an ID in Application layer and Locator in routing space is a bottleneck in future wireless network (FWN) design. Contemporary FWN research is focusing on ID/Locator split concept designs. In this paper we propose an ID/Locator based architecture for MANETs which also solves               auto-configuration requirements for MANETs. Our proposed architecture is an adaptation from available ID/Locator split concepts for infrastructure oriented networks for usage in MANET context. The designed protocol uses identifiers for node identification, node discovery and traffic flow between end points. The protocol support provision for running contemporary IP oriented services. We have also verified various use cases of our proposed protocol through Linux based implementation