<p>Wireless communication has grown very popular, and communication is the key</p><p>to success in many situations. However, most of the common technologies today</p><p>rely on infrastructure and in disaster situations infrastructure might be lost or</p><p>get severely overloaded. This master thesis concerns intermittently connected</p><p>mobile ad hoc networks. A network in which the devices may move freely in any</p><p>direction and still be able to communicate. To be able to demonstrate a network</p><p>protocol called random-walk gossip-based manycast (RWG) my assignment has been</p><p>to implement this protocol using off-the-shelf hardware and software.</p><p>RWG is a multi-hop and partition-tolerant mobile ad hoc manycast network</p><p>protocol. Multi-hop refers to information being able to hop between more than</p><p>two nodes in a network and partition-tolerant means that the protocol works even</p><p>though a network is partitioned. Manycast means that the information should</p><p>be successfully delivered to K of all the potential nodes in the area. The RWG</p><p>protocol makes use of four different packet types, request to forward (REQF), ac-</p><p>knowledgement (ACK), ok to forward (OKTF) and be silent (BS). The actual data</p><p>being sent is carried by REQFs, and is referred to as messages. When a message</p><p>is sent it takes what could be described as a random walk among the nodes in the</p><p>network, hence the name.</p><p>The implementation of the RWG protocol resides in user-space and depends on</p><p>the IEEE 802.11b standard and the raw socket that is specified in the BSD socket</p><p>API. It is written in C and was developed on a machine running Ubuntu. It runs</p><p>on systems that use Linux 2.6 kernels and it supports cross-compiling for ARM</p><p>based devices such as the Nokia N810 internet tablet and the Android dev phone</p><p>1. To be able to demonstrate the protocol I developed my own client application.</p><p>Moreover, an already existing application for Android, Portable Open Search and</p><p>Identification Tool (POSIT), was successfully extended to run on top of the RWG</p><p>implementation. The extension was developed by people in the POSIT project</p><p>and tested in a physical experiment covering five devices.</p><p>The report covers the RWG protocol, the system choice, the implementation</p><p>and the testing of the implementation.</p>

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Zone Routing Protocol (ZRP) is a typical hybrid routing protocol used in Mobile Ad Hoc Networks (MANETs). Hybrid routing protocols are especially suitable for dynamic environments because they combine the best features of proactive and reactive routing protocols. The Gossip-based Zone Routing Protocol (GZRP) uses a gossip scheme, in which the node forwards a packet to some nodes instead of all nodes to further reduce the control overhead. However, GZRP does not perform well when the network includes articulation points since packets will be lost if an articulation node happens not to forward the packet or nodes happen not to forward packets to the articulation point. To raise the packet delivery ratio, the gossip probability of articulation points must be set to 1 and the packets to be forwarded must be sent to the articulation points in peripheral nodes. Accordingly, how to identify articulation nodes in the network becomes a critical issue. This paper proposes an effective scheme, called articulation point detection (APD), to find the articulation points. Simulation results show that the proposed APD-GZRP (GZRP with articulation point detection) can improve the packet delivery ratio and reduce both the control overhead and power consumption.

Broadcasting is a communication model for a node to emit the packets via wireless channels to its neighbor nodes. In mobile ad hoc networks (MANETs), it is commonly implemented through flooding to find routes, send alarm signals and page a particular host. Conventionally, ad hoc routing protocols, such as AODV, use blind flooding extensively for on-demand route discovery, which could result in a high number of redundant retransmissions, leading to serious contention and collisions referred to as the broadcast storm problem. A gossip-based approach, in which each node forwards a message with some probability, has been proposed in past years to alleviate this problem. The approach combines gossiping with AODV (denoted as AODV+G) and exhibits a significant performance improvement in simulations. In this paper, we make a mathematical inference from observing the behavior of the gossip-based approach, and improve the gossip-based approach by employing the remaining energy of nodes in the gossip mechanism (denoted as AODV+GE) to extend the lifetime of the entire network and improve the packet delivery ratio. Through mathematical inference and simulations we show that AODV+GE outperforms AODV+G in terms of the lifetime of the whole network, average node energy consumption, and packet delivery ratio.

A mobile ad hoc network consists of certain nodes that communicate only through wireless medium and can move arbitrarily. The key feature of a mobile ad hoc network is the mobility of the nodes. Because of the mobility, communication links form and disappear as nodes come into and go out of each other's communica- tion range. Mobile ad hoc networks are particularly useful in situations like disaster recovery and search, military operations, etc. Research on mobile ad hoc networks has drawn a huge amount of attention recently. The main challenges for mobile ad hoc networks are the sparse resources and frequent mobility. Most of the research work has been focused on the MAC and routing layer. In this work, we focus on distributed services for mobile ad hoc networks. These services will provide some fundamental functions in developing various applications for mobile ad hoc networks. In particular, we focus on the clock synchronization, connected dominating set, and k-mutual exclusion problems in mobile ad hoc networks.

The evolution of communication networks has led us to an era where you cannot only perform surgery halfway across the world, but do so while being in the comfort of your own home. By eliminating the need for wires, wireless networks revolutionised communication networks by enabling nodes to communicate while being in a mobile state. The concept opened many doors to new applications and possibilities. Network Coding is a technique that optimises the throughput of a network by coding packets. Geo-Routing is a routing method that operates by using the geographical distances between nodes as the routing metric. Opportunistic Routing is a routing method that exploits the broadcast characteristics of wireless networks. In this thesis, we developed a routing scheme that incorporates Network Coding, Geo- Routing and energy aware conditions. It accomplishes this task by using one of the key phases constituting Opportunistic Routing. The developed routing scheme was implemented in OMNeT++. Various simulation experiments were conducted in OMNeT++ pertaining to the implemented scheme. The results indicate significant increase in performance metrics such as throughput and survivability. / Thesis (MIng (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013

The evolution of communication networks has led us to an era where you cannot only perform surgery halfway across the world, but do so while being in the comfort of your own home. By eliminating the need for wires, wireless networks revolutionised communication networks by enabling nodes to communicate while being in a mobile state. The concept opened many doors to new applications and possibilities. Network Coding is a technique that optimises the throughput of a network by coding packets. Geo-Routing is a routing method that operates by using the geographical distances between nodes as the routing metric. Opportunistic Routing is a routing method that exploits the broadcast characteristics of wireless networks. In this thesis, we developed a routing scheme that incorporates Network Coding, Geo- Routing and energy aware conditions. It accomplishes this task by using one of the key phases constituting Opportunistic Routing. The developed routing scheme was implemented in OMNeT++. Various simulation experiments were conducted in OMNeT++ pertaining to the implemented scheme. The results indicate significant increase in performance metrics such as throughput and survivability. / Thesis (MIng (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013

Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN, 2003), deve ser capaz de interagir com as funções de roteamento da Internet, trocando tráfego com a mesma, de modo transparente e eficiente. O protocolo AODV, por ser reativo, pode demorar até 0,05 segundos para estabelecer uma rota entre um nodo origem e um nodo destino. Nos padrões atuais esse tempo pode ser considerado exageradamente alto, gerando gargalos entre sub-redes, descarte de pacotes e baixa eficiência. O presente trabalho apresenta uma proposta de customização do protocolo de roteamento AODV com atuação restrita ao nodo gateway. Esta customização consiste na adição de uma métrica de confiabilidade no processo de descoberta e utilização de rotas visando a redução no número de pacotes descartados e um ganho de eficiência no fluxo de dados entre as sub-redes envolvidas. / A Mobile Ad Hoc Network (MANET) consists of a collection of mobile hosts, moving in certain range area, that has a wireless interface for transmission and receiving data. Usually these terminals make use of radio frequencies in communications and configure a non infrastructured network. The MANETs, also known as independent, require no pre-existing infrastructure to provide communication between network mobile nodes, however, are used, preferably when integrated with the Internet. This integration, although possible, usually need a gateway that forwards packets between both computer networks, keeping their individual characteristics. Problems such as delays and packet losses can be caused by differences inherent in the routing protocols. Although the Internet Engineering Task Force (IETF) proposes several routing protocols for MANETs, this paper investigates the Ad hoc On-Demand Distance Vector (AODV) routing protocol, viewed as one of more implemented and studied protocol by the IETF work group. The gateway node, which is already implemented in the AODV routing protocol (Hamidian, 2003), should be able to interact, transparently and efficiently, with the Internet routing functions exchanging traffic between them. The AODV protocol, being reactive, can take up to 0.05 seconds to establish a route between a source node and a destination node. By today's standards this time may be considered excessively high, creating bottlenecks between subnets, packet drop and low efficiency. This paper proposes an AODV routing protocol customization restricted to the gateway node activities. This customization consists of adding reliability metric in the route discovery process and its consequent use in order to reduce the number of dropped packets and get increased efficiency in the data flow between the subnets involved.

Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN, 2003), deve ser capaz de interagir com as funções de roteamento da Internet, trocando tráfego com a mesma, de modo transparente e eficiente. O protocolo AODV, por ser reativo, pode demorar até 0,05 segundos para estabelecer uma rota entre um nodo origem e um nodo destino. Nos padrões atuais esse tempo pode ser considerado exageradamente alto, gerando gargalos entre sub-redes, descarte de pacotes e baixa eficiência. O presente trabalho apresenta uma proposta de customização do protocolo de roteamento AODV com atuação restrita ao nodo gateway. Esta customização consiste na adição de uma métrica de confiabilidade no processo de descoberta e utilização de rotas visando a redução no número de pacotes descartados e um ganho de eficiência no fluxo de dados entre as sub-redes envolvidas. / A Mobile Ad Hoc Network (MANET) consists of a collection of mobile hosts, moving in certain range area, that has a wireless interface for transmission and receiving data. Usually these terminals make use of radio frequencies in communications and configure a non infrastructured network. The MANETs, also known as independent, require no pre-existing infrastructure to provide communication between network mobile nodes, however, are used, preferably when integrated with the Internet. This integration, although possible, usually need a gateway that forwards packets between both computer networks, keeping their individual characteristics. Problems such as delays and packet losses can be caused by differences inherent in the routing protocols. Although the Internet Engineering Task Force (IETF) proposes several routing protocols for MANETs, this paper investigates the Ad hoc On-Demand Distance Vector (AODV) routing protocol, viewed as one of more implemented and studied protocol by the IETF work group. The gateway node, which is already implemented in the AODV routing protocol (Hamidian, 2003), should be able to interact, transparently and efficiently, with the Internet routing functions exchanging traffic between them. The AODV protocol, being reactive, can take up to 0.05 seconds to establish a route between a source node and a destination node. By today's standards this time may be considered excessively high, creating bottlenecks between subnets, packet drop and low efficiency. This paper proposes an AODV routing protocol customization restricted to the gateway node activities. This customization consists of adding reliability metric in the route discovery process and its consequent use in order to reduce the number of dropped packets and get increased efficiency in the data flow between the subnets involved.

Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN, 2003), deve ser capaz de interagir com as funções de roteamento da Internet, trocando tráfego com a mesma, de modo transparente e eficiente. O protocolo AODV, por ser reativo, pode demorar até 0,05 segundos para estabelecer uma rota entre um nodo origem e um nodo destino. Nos padrões atuais esse tempo pode ser considerado exageradamente alto, gerando gargalos entre sub-redes, descarte de pacotes e baixa eficiência. O presente trabalho apresenta uma proposta de customização do protocolo de roteamento AODV com atuação restrita ao nodo gateway. Esta customização consiste na adição de uma métrica de confiabilidade no processo de descoberta e utilização de rotas visando a redução no número de pacotes descartados e um ganho de eficiência no fluxo de dados entre as sub-redes envolvidas. / A Mobile Ad Hoc Network (MANET) consists of a collection of mobile hosts, moving in certain range area, that has a wireless interface for transmission and receiving data. Usually these terminals make use of radio frequencies in communications and configure a non infrastructured network. The MANETs, also known as independent, require no pre-existing infrastructure to provide communication between network mobile nodes, however, are used, preferably when integrated with the Internet. This integration, although possible, usually need a gateway that forwards packets between both computer networks, keeping their individual characteristics. Problems such as delays and packet losses can be caused by differences inherent in the routing protocols. Although the Internet Engineering Task Force (IETF) proposes several routing protocols for MANETs, this paper investigates the Ad hoc On-Demand Distance Vector (AODV) routing protocol, viewed as one of more implemented and studied protocol by the IETF work group. The gateway node, which is already implemented in the AODV routing protocol (Hamidian, 2003), should be able to interact, transparently and efficiently, with the Internet routing functions exchanging traffic between them. The AODV protocol, being reactive, can take up to 0.05 seconds to establish a route between a source node and a destination node. By today's standards this time may be considered excessively high, creating bottlenecks between subnets, packet drop and low efficiency. This paper proposes an AODV routing protocol customization restricted to the gateway node activities. This customization consists of adding reliability metric in the route discovery process and its consequent use in order to reduce the number of dropped packets and get increased efficiency in the data flow between the subnets involved.