Improved AODV Routing Protocol to Cope with High Overhead in High Mobility MANETs

Ad-hoc On-demand Distance Vector (AODV) is the most popular routing protocol for mobile ad-hoc networks (MANETs). According to its nature, AODV makes route discovery when there is data to send at source and source doesn’t have route to the specified destination. To discover a route to a destination, AODV floods the network with control messages like RREQ, and RREP which may result in unnecessarily large number of control messages that travel through the network and consume network resources such as bandwidth, and node processing power. This thesis improves AODV protocol by limiting the number of AODV control messages forwarded though the network during the route discovery process. By using Global Positioning System (GPS), each node knows its location and its traveling speed stamped by time. Each source node propagates its location and speed stamped by time to other nodes in the network by adding its location information to the generated RREQ packet and HELLO messages. Each node in the network stores location information of other nodes. We propose two protocols to limit control messages flooding in the Ad-hoc networks. The first proposed protocol which is called AODV-LAR uses alternative request region defined in LAR. It uses location information to estimate the location of the destination and then estimates the rectangular search region. To increase the accuracy of the estimation of the search region, the first proposed protocol takes into account the distance that destination node moves during discovery process by adding tolerance factor to the search region. In the second proposed protocol which is called AODV-Line, the intermediate nodes decide to participate in route discovery process according to their distance from the line connecting the source and destination locations without the need of the information about the destination traveling speed. The route discovery search region is adjusted based on the location information of both source and destination. To reduce the delay of route discovery process, AODV-LAR defines an equation to estimate the initial TTL of the RREQ message. We evaluate the performance of the two proposed protocols using two simulation scenarios. The simulation was done using JIST/SWANS simulator. Different performance metrics were measured including routing overhead, number of RREQ messages, delivery ratio, normalized routing load, and delay. The results were compared to the original AODV routing protocol. The results shows that the two proposed protocols outperform the original AODV, where the results report a valuable reduction of overhead , number of RREQ messages sent through the network, and reduction in delay compared to the original AODV. Results also show that the delivery ratio in the proposed protocols is comparable to the delivery ratio in the original AODV protocol

Location-Based Approach for Route Maintenance in Dynamic Source Routing Protocol

Earlier, the idea of mobile computers and ad hoc networks was not on the mind of anyone. All speci¯cations and implementations for the computer networks during that time were designed for wired systems. This is a big challenge for computer engineer since these two systems have di®erent characteristics. Wireless network means dynamic topology, dynamic structure and no infrastructure, while wired network is the opposites. Basically mobile wireless network has the same stan- dard layers of structure, with modi¯cations and functionality that di®er from the earlier networks because of the absence of infrastructure. To facilitate communication within the network, a routing protocol is used to dis- cover routes between nodes. Building a MANET routing protocol is not an easy job, since e±ciency and correctness become the main concern. Some approach had been proposed to make routing protocol becomes e±cient and correct. Dynamic Source Routing (DSR) protocol is known to be a simple routing protocol in MANET. DSR is based on the concept of source routing. For this protocol, mobile nodes are required to maintain route caches that contain the source routes of which the mobile is aware. Entries in the route cache are continually updated as new routes are learned. There are two major phases of the protocol - route discovery and route maintenance Route discovery uses route request and route reply packets. Route maintenance uses route error packets and acknowledgments. Although DSR can respond a route quickly, it yields a long delay when a route is rebuilt. This is because when source node receives RERR packet, it will try to ¯nd alternative routes from route cache. If alternative routes are not available, source node, then, will enter route discovery phase to ¯nd new routes. Finding a route in wireless network require considerable resources, such as time, bandwidth, and power because it relies on broadcasting. In some case any packets may still reach its destination, but with some delay. This delay is very expensive and leads to undesired e®ect, especially in real time networks and the networks with QoS, where the packet delay and packet delivery is the main concern. The objectives of this research are to propose new algorithm to detect route failure as early warning message to the protocol to take further action, and to propose new algorithm for DSR route maintenance to response the early warning message from route failure detection algorithm. The proposed algorithms based on node location information that may be collected through Global Positioning System (GPS). This thesis introduces two new route maintenance strategies by utilizing node location information. These new route maintenance strategies are called as DIS- TANCE (DIstance baSed rouTe maintenANCE) and ADISTANCE (Adaptive DISTANCE). The algorithms work by adding another node (called bridge node) into the source list to prevent the link from failure. From the simulation result, both algoritmns improves the performance of DSR in terms of packet sending ratio, delay and routing overhead.This thesis introduces two new route maintenance strategies by utilizing node location information. These new route maintenance strategies are called as DIS- TANCE (DIstance baSed rouTe maintenANCE) and ADISTANCE (Adaptive DISTANCE). The algorithms work by adding another node (called bridge node) into the source list to prevent the link from failure. From the simulation result, both algoritmns improves the performance of DSR in terms of packet sending ratio, delay and routing overhead

Proximity aware routing in ad hoc networks

Most of the existing routing protocols for ad hoc networks are designed to scale in networks of a few hundred nodes. They rely on state concerning all links of the network or links on the route between a source and a destination. This may result in poor scaling properties in larger mobile networks or when node mobility is high. Using location information to guide the routing process is one of the most often proposed means to achieve scalability in large mobile networks. However, locationbased routing is difficult when there are holes in the network topology. We propose a novel positionbased routing protocol called Proximity Aware Routing for Ad-hoc networks (PARA) to address these issues. PARA selects the next hop of a packet based on 2-hops neighborhood information. We introduce the concept of “proximity discovery”. The knowledge of a node’s 2-hops neighborhood enables the protocol to anticipate concave nodes and helps reduce the risks that the routing protocol will reach a concave node in the network. Our simulation results show that PARA’s performance is better in sparse networks with little congestion. Moreover, PARA significantly outperforms GPSR for delivery ratio, transmission delay and path length. Our results also indicate that PARA delivers more packets than AODV under the same conditions

Routing and Security in Mobile Ad Hoc Networks

A Mobile Ad hoc Network (MANET) consists of a set of nodes which can form a network among themselves. MANETs have applications in areas such as military, disaster rescue operations, monitoring animal habitats, etc. where establishing fixed communication infrastructure is not feasible. Routing protocols designed for MANETs can be broadly classified as position-based (geographic), topology-based and hybrid. Geographic routing uses location information of nodes to route messages. Topology-based routing uses network state information for route discovery and maintenance. Hybrid routing protocols use features in both position-based and topology-based approaches. Position-based routing protocols route packets towards the destination using greedy forwarding (i.e., an intermediate node forwards packets to a neighbor that is closer to the destination than itself). If a node has no neighbor that is closer to the destination than itself, greedy forwarding fails. In this case, we say there is void. Different position-based routing protocols use different methods for dealing with voids. Topology-based routing protocols can be classified into on-demand (reactive) routing protocols and proactive routing protocols. Generally, on-demand routing protocols establish routes when needed by flooding route requests throughout the entire network, which is not a scalable approach. Reactive routing protocols try to maintain routes between every pair of nodes by periodically exchanging messages with each other which is not a scalable approach also. This thesis addresses some of these issues and makes the following contribution. First, we present a position-based routing protocol called Greedy Routing Protocol with Backtracking (GRB) which uses a simple backtracking technique to route around voids, unlike existing position-based routing protocols which construct planarized graph of the local network to route around voids. We compare the performance of our protocol with the well known Greedy Perimeter Stateless Routing (GPSR) protocol and the Ad-Hoc On-demand Distance Vector (AODV) routing protocol as well as the Dynamic Source Routing (DSR) protocol. Performance evaluation shows that our protocol has less control overhead than those of DSR, AODV, and GPSR. Performance evaluation also shows that our protocol has a higher packet-delivery ratio, lower end-to-end delay, and less hop count, on average, compared to AODV, DSR and GPSR. We then present an on-demand routing protocol called ``Hybrid On-demand Greedy Routing Protocol with Backtracking for Mobile Ad-Hoc Networks which uses greedy approach for route discovery. This prevents flooding route requests, unlike the existing on-demand routing protocols. This approach also helps in finding routes that have lower hop counts than AODV and DSR. Our performance evaluation confirms that our protocol performs better than AODV and DSR, on average, with respect to hop count, packet-delivery ratio and control overhead. In MANETs, all nodes need to cooperate to establish routes. Establishing secure and valid routes in the presence of adversaries is a challenge in MANETs. Some of the well-known source routing protocols presented in the literature (e.g., Ariadne and endairA) which claim to establish secure routes are susceptible to hidden channel attacks. We address this issue and present a secure routing protocol called SAriadne, based on sanitizable signatures. We show that our protocol detects and prevents hidden channel attacks

Improving the Performance of Routing Protocol Using Neighbor Coverage Based Probabilistic Rebroadcast in Mobile Ad Hoc Network

Mobile Ad Hoc Networks provides important control and route establishment functionality for a number of unicast an d multicast protocols. To discover an effective and an efficient routing protocol for transmit information from source to destination across whole network topology. This is a main issue in networking research. Broadcasting is important in MANET for routing infor mation discovery, protocols such as ad hoc on demand distance vector (AODV), dynamic source routing (DSR), and location aided routing use broadcasting to establish routes. Broadcasting in MANETs poses more challenging problems because of the variable and unpredictable characteristics of its medium as well as the fluctuation of the signal strength and propagation with respect to time and environment such as bandwidth congestion, channel contention problem, and packet collision problem. To overcome the se and reducing routing overhead we did study about neighbor coverage based probabilistic rebroadcast protocol in MANETs. In order to effectively exploit the neighbor coverage knowledge, we also discuss a connectivity factor to provide the node density ada ptation. Our approach combines the advantages of the neighbor coverage knowledge and the probabilistic mechanism, which can significantly, optimizes the routing mechanism in comparison to the AODV protocol. We just complete our dissertation work by compari ng AODV protocol with the new concept of rebroadcasting is NCPR in point of many performance metrics. The performance results and comparisons are done by using NS - 2 simulator

DIRECTIONAL ANTENNA BASED EFFICIENT LOCATION AWARE ROUTING IN MOBILE ADHOC NETWORK

Mobile Adhoc Network (MANET) also called as wireless ad hoc network is a self-organizing, self-configuring infrastructure less network containing a group of mobile nodes communicating wirelessly. As the hosts move often resulting in dynamic topology of the network, routing seeks more attention. Therefore, routing protocol using node’s location information like LAR (location aided routing) has emerged as potential solution. Here, the route discovery is limited to a small region named as request zone in contrast to blind flooding over the entire network. Also it is noticeable that the shape and size of the request zone play a vital role in enhancing the protocol’s performance. After various analyses it was concluded that for higher node density, elliptical shaped request zone performs better than other possible shapes. Further, suitable route must be chosen based on current load status of the network so that successful delivery of packets is ensured. Generally, omni-directional antennas are used for communication between moving motes. The disadvantage of mobile ad hoc networks with omni-directional antenna lies in the limited capacity caused by high interference and low spatial reuse. This paper focuses on obtaining optimal size for request zone in accordance with varying node density. Further, optimal path between source and destination is selected using Dijkstra’s algorithm. Our simulation results show that directional antennas outshines the performance of omni-directional antennas in increasing transmission range of nodes, reducing the number of redundant nodes involving in data communication etc

Energy Efficient Location Aided Routing Protocol for Wireless MANETs

A Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without using any centralized access point, infrastructure, or centralized administration. In this paper we introduce an Energy Efficient Location Aided Routing (EELAR) Protocol for MANETs that is based on the Location Aided Routing (LAR). EELAR makes significant reduction in the energy consumption of the mobile nodes batteries by limiting the area of discovering a new route to a smaller zone. Thus, control packets overhead is significantly reduced. In EELAR a reference wireless base station is used and the network's circular area centered at the base station is divided into six equal sub-areas. At route discovery instead of flooding control packets to the whole network area, they are flooded to only the sub-area of the destination mobile node. The base station stores locations of the mobile nodes in a position table. To show the efficiency of the proposed protocol we present simulations using NS-2. Simulation results show that EELAR protocol makes an improvement in control packet overhead and delivery ratio compared to AODV, LAR, and DSR protocols.Comment: 9 Pages IEEE format, International Journal of Computer Science and Information Security, IJCSIS 2009, ISSN 1947 5500, Impact factor 0.423, http://sites.google.com/site/ijcsis

Efficient route discovery for reactive routing

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Information on the location of mobile nodes in Mobile Ad-hoc Networks (MANETs) has the potential to significantly improve network performance. This thesis uses node location information to develop new techniques for route discovery in on-demand routing protocols such as the Ad-hoc On-Demand Distance Vector (AODV), thus making an important contribution to enhancing the experience of using mobile networks. A Candidate Neighbours to Rebroadcast the Route Request (CNRR) approach has been proposed to reduce the deleterious impact, known as the broadcast storm, of RREQ packets flooding in traditional on-demand routing protocols. The main concept behind CNRR is specifying a set of neighbours which will rebroadcast the received RREQ. This is a departure from the traditional approach of all receiving nodes rebroadcasting RREQs and has the effect of reducing the problem of redundancy from which mobile networks suffer. The proposed protocol has been developed in two phases: Closest-CNRR and Furthest-CNRR. The simulation results show that the proposed algorithms have a significant effect as they reduce the routing overhead of the AODV protocol by up to 28% compared to the C-CNRR, and by up to 17.5% compared to the F-CNRR. Notably, the proposed algorithms simultaneously achieve better throughput and less data dropping. The Link Stability and Energy Aware protocol (LSEA) has been developed to reduce the overhead while increasing network lifetimes. The LSEA helps to control the global dissemination of RREQs in the network by eliminating those nodes that have a residual energy level below a specific threshold value from participation in end-to-end routes. The proposed LSEA protocol significantly increases network lifetimes by up to 19% compared with other on-demand routing protocols while still managing to obtain the same packet delivery ratio and network throughput levels. Furthermore, merging the LSEA and CNRR concepts has the great advantage of reducing the dissemination of RREQs in the network without loss of reachability among the nodes. This increases network lifetimes, reduces the overhead and increases the amount of data sent and received. Accordingly, a Position-based Selective Neighbour (PSN) approach has been proposed which combines the advantages of zoning and link stability. The results show that the proposed technique has notable advantages over both the AODV and MAAODV as it improves delivery ratios by 24.6% and 18.8%, respectively.Funded by National Council for Training - Sudan and the Sudan Academy of Science

A Review of the Energy Efficient and Secure Multicast Routing Protocols for Mobile Ad hoc Networks

This paper presents a thorough survey of recent work addressing energy efficient multicast routing protocols and secure multicast routing protocols in Mobile Ad hoc Networks (MANETs). There are so many issues and solutions which witness the need of energy management and security in ad hoc wireless networks. The objective of a multicast routing protocol for MANETs is to support the propagation of data from a sender to all the receivers of a multicast group while trying to use the available bandwidth efficiently in the presence of frequent topology changes. Multicasting can improve the efficiency of the wireless link when sending multiple copies of messages by exploiting the inherent broadcast property of wireless transmission. Secure multicast routing plays a significant role in MANETs. However, offering energy efficient and secure multicast routing is a difficult and challenging task. In recent years, various multicast routing protocols have been proposed for MANETs. These protocols have distinguishing features and use different mechanismsComment: 15 page