Tesi sul tema "ADHOC ON-DEMAND DISTANCE VECTOR"

This thesis contains a theoretical basis for MANET networks. The main focus of the thesis is principles of these networks, their routing protocols and especially on Ad hoc On-Demand Distance Vector (AODV), implementation of this protocol and implementation of new mechanis for peer selection. Thesis contains ETX metric basic and implementation of this metric to AODV protocol. There is a demonstration of simulation of AODV protocol and simulation of AODV-ETX protocol. Simulations are run in Network Simulator 3. AODV and AODV-ETX comparasion are included in thesis.

The ad hoc on-demand distance vector (AODV) routing protocol offers quick adaptation to dynamic link changes, incurs low processing and memory overhead, has a low initial setup while connecting to networks, and determines unicast routes to destinations within the ad hoc network. This routing protocol allows for efficient and reliable discovery of routes. Although the connection setup delay is lower for the AODV protocol compared to other ad hoc routing protocols, such as the dynamic source routing (DSR) protocol and destination sequenced distance vector (DSDV) protocol, the AODV routing protocol involves a heavy control overload and delay while finding the routes in adverse conditions, such as the presence of malicious nodes in the network or connection failures due to network congestion. This thesis studies the secure message transmission (SMT) protocol, which safeguards data transmission against arbitrary malicious behavior of other nodes and evaluates its performance over the AODV routing protocol. The analysis of the performance of the AODV routing protocol in combination with the SMT protocol was done by considering a scenario of mobile ad hoc networks under adverse conditions, with half of the nodes acting maliciously and dropping both data and control packets. The AODV routing protocol in combination with the SMT protocol imposes up to 46% less routing overhead, delivering up to 17% more data packets, with a throughput of 12% more and end-to-end delays that are up to 24% lower than those of the native AODV routing protocols in the scenarios considered. Thus the AODV routing protocol performs well with the SMT protocol, and is reliable. The NS-2 network simulator was utilized to compare performances. The advantages of the proposed approach of using the AODV routing protocol together with the SMT protocol are more apparent in the presence of malicious nodes in the network.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

The aim of this research is to improve routing fault tolerance in Mobile Ad hoc Networks (MANETs) by optimising mUltipath routing in a well-studied reactive and single path routing protocol known as Ad hoc On-demand Distance Vector (AODV). The research also aims to prove the effect of varying waiting time of Route Reply (RREP) procedure and utilising the concept of efficient routes on the performance of multipath extensions to AODV. Two novel multipath routing approaches are developed in this thesis as new extensions to AODV to optimise routing overhead by improving Route Discovery Process (RDP) and Route Maintenance Process (RMP) of multipath AODV. The first approach is a Iinkdisjoint multipath extension called 'Thresho)d efficient Routes in multipath AODV' (TRAODV) that optimises routing packets ~verhead by improving the RDP of AODV which is achieved by detecting the waiting time required for RREP procedure to receive a threshold number of efficient routes. The second approach is also a link-disjoint mUltipath extension called 'On-demand Route maintenance in Multipath AoDv' (ORMAD) which is an extension to TRAODV that optimises routing packets and delay overhead by improving the RMP of TRAODV. ORMAD applies the concepts of threshold waiting time and efficient routes to both phases RDP and RMP. It also applies RMP only to efficient routes which are selected in the RDP and when a route fails, it invokes a local repair procedure between upstream and downstream nodes of the broken link. This mechanism produces a set of alternative subroutes with less number of hops which enhances route efficiency and consequently minimises the routing overhead. TRAODV and ORMAD are implemented and evaluated against two existing multipath extensions to,AODV protocol and two traditional multipath protocols. The existing extensions to AODV used in the evaluation are a well-known protocol called Ad hoc On-demand Multipath Distance Vector (AOMDV) and a recent extension called Multiple Route AODV (MRAODV) protocol which is extended in this thesis to the new approach TRAODV while the traditional multipath protocols used in the evaluation are Dynamic Source Routing (DSR) and Temporally Ordered Routing Algorithm (TORA). Protocols are implemented using NS2 and evaluated under the same simulation environment in terms of four performance metrics; packet delivery fraction, average end-to-end delay, routing packets overhead, and throughput. Simulation results of TRAODV evaluation show that the average number of routes stored in a routing table of MRAODV protocol is always larger than the average number of routes in TRAODV. Simulation results show that TRAODV reduces the overall routing packets overhead compared to both extensions AOMDV and MRAODV, especially for large network size and high mobility. A vital drawback of TRAODV is that its performance is reduced compared to AOMDV and MRAODV in terms of average end-to-end delay. Additionally, TORA still outperforms TRAODV and the other extensions to AODV in terms of routing packets overhead. In order to overcome the drawbacks of TRAODV, ORMAD is developed by improving the RDP of TRAODV. The performance of ORMAD is evaluated against RREP waiting time using the idea of utilising the efficient routes in both phases RDP and RMP. Simulation results of ORMAD show that the performance is affected by varying the two RREP waiting times of both RDP and RMP in different scenarios. As shown by the simulation results, applying the short and long waiting times in both phases tends to less performance in terms of routing packets overhead while applying the moderate waiting times tends to better performance. ORMAD enhances routing packets overhead and the average end-to-end delay compared to TRAODV, especially in high mobility scenarios. ORMAD has the closest performance to TORA protocol in terms of routing packets overhead compared to ~M~a~M~OW . Relevant concepts are formalised for ORMAD approach and conducted as an analytical model in this thesis involving the\vhole process of multipath routing in AODV extensions. ORMAD analytical model describes how the two phases RDP and RMP interact with each other with regard to two performance metrics; total number of detected routes and Route Efficiency.

Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, Dec. 2000.
Thesis advisor(s): Tummala, Murali. "December 2000." Includes bibliographical references (p. 81-82). Also available in print.

The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks. The second goal of this thesis was to investigate the blocking problem induced by Request-to-Send/Clear-to-Send (RTS/CTS) mechanism in detail and provide a solution to overcome that problem. To do so, a new parameter is proposed by which the Medium Access control (MAC) protocol will decide when to switch between RTS/CTS mechanism (the 4-way-handshaking) and the Basic Access method (the 2-way-handshaking) in order to reduce the effect of the blocking problem in Ad Hoc networks.

The importance of communication is vital in wartime. The capability of having all the position information of the allied and enemy forces in a single Tactical Information Display System (TIDS), maintains a great advantage for deciding what to do before the enemy reacts. A Naval Information Distributing System (NIDS) is developed for building an effective communication infrastructure between the war ships. In the designed network, besides the mobile platforms (ships), some fixed platforms (land stations) are used to transfer the information coming from these mobile platforms to all the other platforms. To demonstrate the performance and effectiveness of the Naval Information Distribution System, a discrete event simulation model is developed on a Geographic Information System. The goal of this thesis is to describe and experimentally evaluate an effective and feasible information sharing and routing system for Navy.

The Parking Guidance and Information (PGI) system is an important application of Intelligent Transport System (ITS), which has been shown to be an effect service for traffic information and parking management. The roadside Variable Message Sign (VMS) board has been the usual media for the publication of parking information in early PGI systems, and its performance over the years has been studied via simulations and questionnaire surveys. However, survey results show significant discrepancies across various traffic networks in different areas. More recently, parking information services have become available on other media such as mobile and in-vehicle devices. In contrast to VMS-based systems, PGI systems based on new media, especially the in-vehicle class of devices, have not been studied separately. This thesis aims to conduct research into the performance of PGI systems based on invehicle devices, by simulating and comparing a VMS-based PGI system with a Vehicle On-Board Device (VOBD)-based PGI system. A specially designed simulator utilising a routing algorithm known as the Ad hoc On-Demand Distance Vector (AODV) routing protocol in computer networks, has been created in MATLAB. The simulation minimises the influence of specific structures of traffic networks that may be found in some networks, but not others. This is done by simulating a grid-based road network where the capacities of parking stations and their geographic distribution are randomly allocated within specific zones, and the parking demand in each run of simulations is variable load. The results of simulations, including the information reliability, reduction of travel time, demand on on-street parking and the utilisation rates of parking stations, are analysed for multiple scenarios where the compliance rate, the information update policy and the strategy of human behaviour are varied. The analyses reveal a significant advantage of VOBD-based PGI systems over VMS-based PGI systems in terms of the quality of information and the reduction of travel time. At the same time, the analyses highlight the limitations of a PGI system when the demand and supply of parking stations is not appropriately balanced.

Wireless devices use has been increased drastically in the last decade. To provide communication between the node which are mobile in nature and using wireless network some protocols were developed to provide faster transmission between the nodes in the network. But most of them lack in conserving the energy of the nodes to maximize the network lifetime. Energy is the main constraint in a wireless network. Each network device is running on the battery which is always limited source of energy. Hence the routing protocol should take energy of nodes as a valuable metric to perform routing which results in maximum network lifetime. Several protocols were already developed for routing in Mobile Adhoc Network (MANET) in this dissertation we enhance the Adhoc On-Demand Distance Vector (AODV) and Distance Sequenced Distance Vector (DSDV) which is widely used for routing in MANET’s. This dissertation improves AODV, DSDV protocol to optimize the routing which preserves energy to increase the network lifetime.

碩士
國立宜蘭大學
資訊工程研究所碩士班
97
In order to move towards the current development of ubiquitous network environment. To integrate the different types of network environment is going on. The IEEE 802.15.4 standard is a low cost, low-rate, Low-power Wireless Personal Area Network technology. IP for Smart Objects seeks to extend the use of IP networking into resource-constrained devices over a low-power network. IPv6 over Low-power Wireless Personal Area Network (6LoWPAN) are specified by the IETF Working Group, and advanced by the IPSO alliance. 6LoWPAN Ad Hoc On-Demand Distance Vector Routing (LOAD) is based on AODV , and simplify the routing protocol for 6LoWPAN mesh network . Although the LOAD simplify the AODV for 6LoWPAN mesh network, but the route discovery by broadcasting route request(RREQ) still huge whole network overhead . So we would like to use the concept of Ad-Hoc On-Demand Multipath Distance Vector Routing (AOMDV) for LOAD to find multipath routes during the route discovery. If the path fail we still have alternate path can be used for reducing the overhead of route discovery for the network.

碩士
華梵大學
工業工程與經營資訊學系碩士班
97
With the popularities of mobile devices and their applications, the mobile Ad-Hoc network becomes an important research topic. Different from typical networks that have fixed topologies, the movement of mobile nodes leads to the change of network topology that influences the network’s behavior. This research uses simulation models to study the parameters that affect the network’s stability and performance. Network structures and routing protocols were first investigated to establish the basis of simulation infrastructure and the Ad-Hoc On-Demand Distance Vector communication protocol was selected to develop the models. The simulation platform was developed using AnyLogic which is object-oriented simulation development software in Java language. Speed, mobility and distribution of mobile nodes were used as parameters in the simulation. The simulation results indicate that the topology change is the most important parameter that affects the data transmission performance of Ad-Hoc On-Demand Distance Vector protocol. In order to maintain a certain degree of stability these parameters must be within a proper range.

A mobile ad hoc network (MANET) is a collection of mobile nodes that form a wireless network without the use of a fixed infrastructure or centralized administration, and every node acts as a host as well as a router. The topology of an ad hoc network changes frequently and unpredictably. The mobile nature and dynamic topology of MANETs make it very difficult to provide Quality-of-Service (QoS) assurance in such networks. Considering the limited bandwidth and battery power, finding routes that satisfy the bandwidth constraint of applications is a significant challenge. Ad hoc on-demand distance vector routing (AODV) is an on-demand routing protocol that only provides best-effort routes. QS-AODV is proposed in this thesis. It is based on AODV and creates routes according to the QoS requirements of the applications. It is shown that QS-AODV provides performance comparable to AODV under light traffic. In heavy traffic, QS-AODV provides higher packet delivery ratios and lower routing overheads, at a cost of slightly longer end-to-end delays as the routes in QS-AODV are not always the shortest. The effects of network size and mobility on the performance of QSAODV are shown.

碩士
國立臺中教育大學
資訊工程學系
104
With the development of Mobile Ad hoc Networks (MANET), and the mobility of nodes, network topologies may change constantly. Ad hoc On-demand Multipath Distance Vector routing (AOMDV) is a common routing protocol, which modified the AODV protocol to reduce the delay and consumption while restarting the route discovery by multipath extensions. If the route breaks while transferring, the packet will be send through the alternate paths. With limited resources in MANET, the node may have selfish behaviors to reduce its consumption, but the original AOMDV method does not take into account the presence of selfish nodes. Therefore, to maintain the security of the transmission path, we modified the AOMDV, and proposed Guard node-based Ad hoc On-demand Multipath Distance Vector routing (GAOMDV) method by introducing guard nodes to monitor the transmission path. First, guard nodes around the senders on the transmission path will monitor the transmission. Moreover, the sender may launch a simple agreement mechanism to find out the suspicious selfish and/or malicious nodes. The results observed by the guard nodes will be sent to the sender for making routing decisions. Finally, based on the voting results, the sender determines whether the primary transmission path should be replaced by the other paths or not. We use NS2 simulator to compare AOMDV and GAOMDV, with different ratios of selfish nodes and different voting thresholds, and to observe transfer rate and packet delay. To find other malicious nodes hidden in the voting nodes, we designed a simple game to find the best voting strategy.

There is a lot of alternative routing protocols used in wireless communications. One of these protocols is Ad Hoc On-Demand Distance Vector routing protocol (AODV). This protocol is used in the mobile ad-hoc networks which are self-configuring networks consisting of the independent mobile devices where each one of these devices acts as a router and forwards traffic from other devices. AODV protocol uses hop count as a routing metric, but in the many cases this metric is not optimal in the wireless networks. The goal of this thesis is to propose the alternative criteria which can be used to select best routes. An integral part of this thesis is the experimental implementations of suggested metrics which will be simulated and evaluated in the selected simulation tool. The conclusion of the thesis analyses results obtained from the simulations of the individual suggested versions.

A Mobile Ad Hoc Network (MANETs) is a collection of wireless hosts that can be rapidly deployed as a multi hop packet radio network without the aid of any established infrastructure or centralized administration. Such networks can be used to enable next generation of battlefield applications envisioned by the military, including situation awareness systems for maneuvering war fighters, and remotely deployed unmanned microsensor networks. Ad Hoc networks can also provide solutions for civilian applications such as disaster recovery and message exchanges among safety and security personnel involved in rescue missions. Existing solutions for wired network Intrusion Detection Systems (IDSs) do not suit wireless Ad Hoc networks. To utilize either misuse detection or anomaly detection to monitor any possible compromises, the IDS must be able to distinguish normal from anomaly activities. To enable intrusion detection in wireless Ad Hoc networks, the research problems are: • How to efficiently collect normal and anomaly patterns of Ad Hoc networks? The lifetime of the hosts is short and Ad Hoc networks do not have traffic concentration points (router, switch). • How to detect anomalies? The loss could be caused by host movement instead of attacks. Unexpectedly long delay could be caused by unreliable channel instead of malicious discard. In this thesis, we have proposed a novel architecture that uses specification based intrusion detection techniques to detect active attacks against the routing protocols of mobile Ad Hoc networks. Our work analyzes some of the vulnerabilities and discuss the attacks against the AODV protocol. Our approach involves the use of an FSM (Finite State Machine) for specifying the AODV routing behavior and the distributed network monitors for detecting the sequence number attack. Our method can detect most of the bad nodes with low false positive rate and the packet delivery ratio can also be increased with high detection rate. For packet dropping attack, we present a distributed technique to detect this attack in wireless Ad Hoc networks. A bad node can forward packets but in fact it fails to do so. In our technique, every node in the network will check the neighboring nodes to detect if any of them fail to forward the packets. Our technique can detect most of the bad nodes with low false positive rate and the packet delivery ratio can also be increased. The proposed solution can be applied to identify multiple malicious nodes cooperating with each other in MANETs and discover secure routes from source to destination by avoiding malicious nodes acting in cooperation. Our technique will detect the sequence number and Packet Dropping attacks in real time within its radio range with no extra overhead. For resource consumption attack, the proposed scheme incurs no extra overhead, as it makes minimal modifications to the existing data structures and functions related to bad listing a node in the existing version of pure AODV. The proposed scheme is more efficient in terms of the resultant routes established, resource reservations, and computational complexity. If multiple malicious nodes collaborate, they in turn will be restricted and isolated by their neighbors, because they monitor and exercise control over forwarding RREQs by nodes. Hence, the scheme successfully prevents Distributed attacks. The proposed scheme shifts the responsibility of monitoring this parameter to the node's neighbor, ensuring compliance of this restriction. This technique solves all of the problems caused due to unnecessary RREQs from a compromised node. Instead of self-control, the control exercised by a node's neighbor results in preventing this attack. Experiments show that the tool provides effective intrusion detection functionality while using only a limited amount of resources. The loop freedom property has been reduced to an invariant on pairs of nodes. Each node decides & transmits its decision to a control center. Robustness to Threats, Robustness to nodes destruction: Loss of Performance (in terms of ratio) is least for Distributed Option and highest for Centralized Option and Robustness to observations deletion. All the proposed schemes were analyzed and tested under different topologies and conditions with varying number of nodes .The proposed algorithms for improving the robustness of the wireless Ad Hoc networks using AODV protocol against Packet Dropping Attack, Sequence Number attack and resource consumption attack have been simulated for an illustrative network of about 30 nodes. Our experiments have shown that the pattern extracted through simulation can be used to detect attacks effectively. The patterns could also be applied to detect similar attacks on other protocols.

A Mobile Ad Hoc Network (MANETs) is a collection of wireless hosts that can be rapidly deployed as a multi hop packet radio network without the aid of any established infrastructure or centralized administration. Such networks can be used to enable next generation of battlefield applications envisioned by the military, including situation awareness systems for maneuvering war fighters, and remotely deployed unmanned microsensor networks. Ad Hoc networks can also provide solutions for civilian applications such as disaster recovery and message exchanges among safety and security personnel involved in rescue missions. Existing solutions for wired network Intrusion Detection Systems (IDSs) do not suit wireless Ad Hoc networks. To utilize either misuse detection or anomaly detection to monitor any possible compromises, the IDS must be able to distinguish normal from anomaly activities. To enable intrusion detection in wireless Ad Hoc networks, the research problems are: • How to efficiently collect normal and anomaly patterns of Ad Hoc networks? The lifetime of the hosts is short and Ad Hoc networks do not have traffic concentration points (router, switch). • How to detect anomalies? The loss could be caused by host movement instead of attacks. Unexpectedly long delay could be caused by unreliable channel instead of malicious discard. In this thesis, we have proposed a novel architecture that uses specification based intrusion detection techniques to detect active attacks against the routing protocols of mobile Ad Hoc networks. Our work analyzes some of the vulnerabilities and discuss the attacks against the AODV protocol. Our approach involves the use of an FSM (Finite State Machine) for specifying the AODV routing behavior and the distributed network monitors for detecting the sequence number attack. Our method can detect most of the bad nodes with low false positive rate and the packet delivery ratio can also be increased with high detection rate. For packet dropping attack, we present a distributed technique to detect this attack in wireless Ad Hoc networks. A bad node can forward packets but in fact it fails to do so. In our technique, every node in the network will check the neighboring nodes to detect if any of them fail to forward the packets. Our technique can detect most of the bad nodes with low false positive rate and the packet delivery ratio can also be increased. The proposed solution can be applied to identify multiple malicious nodes cooperating with each other in MANETs and discover secure routes from source to destination by avoiding malicious nodes acting in cooperation. Our technique will detect the sequence number and Packet Dropping attacks in real time within its radio range with no extra overhead. For resource consumption attack, the proposed scheme incurs no extra overhead, as it makes minimal modifications to the existing data structures and functions related to bad listing a node in the existing version of pure AODV. The proposed scheme is more efficient in terms of the resultant routes established, resource reservations, and computational complexity. If multiple malicious nodes collaborate, they in turn will be restricted and isolated by their neighbors, because they monitor and exercise control over forwarding RREQs by nodes. Hence, the scheme successfully prevents Distributed attacks. The proposed scheme shifts the responsibility of monitoring this parameter to the node's neighbor, ensuring compliance of this restriction. This technique solves all of the problems caused due to unnecessary RREQs from a compromised node. Instead of self-control, the control exercised by a node's neighbor results in preventing this attack. Experiments show that the tool provides effective intrusion detection functionality while using only a limited amount of resources. The loop freedom property has been reduced to an invariant on pairs of nodes. Each node decides & transmits its decision to a control center. Robustness to Threats, Robustness to nodes destruction: Loss of Performance (in terms of ratio) is least for Distributed Option and highest for Centralized Option and Robustness to observations deletion. All the proposed schemes were analyzed and tested under different topologies and conditions with varying number of nodes .The proposed algorithms for improving the robustness of the wireless Ad Hoc networks using AODV protocol against Packet Dropping Attack, Sequence Number attack and resource consumption attack have been simulated for an illustrative network of about 30 nodes. Our experiments have shown that the pattern extracted through simulation can be used to detect attacks effectively. The patterns could also be applied to detect similar attacks on other protocols.