48 research outputs found

    Design and evaluation of dynamic policy-based flow redirection for multihomed mobile netwotks

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    This paper presents the design, implementation and evaluation of a solution for dynamic redirection of traffic flows for multihomed mobile networks. The solution was developed for a mobile user that disposes of a Personal Area Network (PAN) with a Personal Mobile Router (PMR), in order to achieve Always Best Connected(ABC) service by distributing flows belonging to different applications among the most appropriate access networks. Designed in a modular way for a NEMO based mobility and multihoming support, the proposed flow redirection solution can be easily coupled with and controlled by dynamic traffic policies that come from advanced network intelligence, according to the currently available network resources and user and application requirements. A prototype implementation was validated and assessed on a testbed as proof-of-concept

    Mobility as a first class function

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    Seamless host mobility has been a desirable feature for a long time, but was not part of the original design of the Internet architecture or protocols. Current approaches to network-layer mobility typically require additional network-layer entities for mobility management, which add complexity to the current engineering landscape of the Internet. We present a host-based, end-to-end architecture for host mobility using the Identifier-Locator Network Protocol (ILNP). ILNP provides mobility support as a first class function, since mobility management is controlled and managed by the end-systems, and does not require additional network-layer entities. We demonstrate an instance of ILNP that is a superset of IPv6 – called ILNPv6 – that is implemented by extending the current IPv6 code in the Linux kernel. We make a direct comparison of performance of ILNPv6 and Mobile IPv6, showing the improved performance of ILNPv6.Postprin

    Game theory for dynamic spectrum sharing cognitive radio

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    ‘Game Theory’ is the formal study of conflict and cooperation. The theory is based on a set of tools that have been developed in order to assist with the modelling and analysis of individual, independent decision makers. These actions potentially affect any decisions, which are made by other competitors. Therefore, it is well suited and capable of addressing the various issues linked to wireless communications. This work presents a Green Game-Based Hybrid Vertical Handover Model. The model is used for heterogeneous wireless networks, which combines both dynamic (Received Signal Strength and Node Mobility) and static (Cost, Power Consumption and Bandwidth) factors. These factors control the handover decision process; whereby the mechanism successfully eliminates any unnecessary handovers, reduces delay and overall number of handovers to 50% less and 70% less dropped packets and saves 50% more energy in comparison to other mechanisms. A novel Game-Based Multi-Interface Fast-Handover MIPv6 protocol is introduced in this thesis as an extension to the Multi-Interface Fast-handover MIPv6 protocol. The protocol works when the mobile node has more than one wireless interface. The protocol controls the handover decision process by deciding whether a handover is necessary and helps the node to choose the right access point at the right time. In addition, the protocol switches the mobile nodes interfaces ‘ON’ and ‘OFF’ when needed to control the mobile node’s energy consumption and eliminate power lost of adding another interface. The protocol successfully reduces the number of handovers to 70%, 90% less dropped packets, 40% more received packets and acknowledgments and 85% less end-to-end delay in comparison to other Protocols. Furthermore, the thesis adapts a novel combination of both game and auction theory in dynamic resource allocation and price-power-based routing in wireless Ad-Hoc networks. Under auction schemes, destinations nodes bid the information data to access to the data stored in the server node. The server will allocate the data to the winner who values it most. Once the data has been allocated to the winner, another mechanism for dynamic routing is adopted. The routing mechanism is based on the source-destination cooperation, power consumption and source-compensation to the intermediate nodes. The mechanism dramatically increases the seller’s revenue to 50% more when compared to random allocation scheme and briefly evaluates the reliability of predefined route with respect to data prices, source and destination cooperation for different network settings. Last but not least, this thesis adjusts an adaptive competitive second-price pay-to-bid sealed auction game and a reputation-based game. This solves the fairness problems associated with spectrum sharing amongst one primary user and a large number of secondary users in a cognitive radio environment. The proposed games create a competition between the bidders and offers better revenue to the players in terms of fairness to more than 60% in certain scenarios. The proposed game could reach the maximum total profit for both primary and secondary users with better fairness; this is illustrated through numerical results.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Delay-centric handover in SCTP

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    The introduction of the Stream Control Transmission Protocol (SCTP) has opened the possibility of a mobile aware transport protocol. The multihoming feature of SCTP negates the need for a solution such as Mobile IP and, as SCTP is a transport layer protocol, it adds no complexity to the network. Utilizing the handover procedure of SCTP, the large bandwidth of WLAN can be exploited whilst in the coverage of a hotspot, and still retain the 3G connection for when the user roams out of the hotspot’s range. All this functionality is provided at the transport layer and is transparent to the end user, something that is still important in non-mobile-aware legacy applications. However, there is one drawback to this scenario - the current handover scheme implemented in SCTP is failure-centric in nature. Handover is only performed in the presence of primary destination address failure. This dissertation proposes a new scheme for performing handover using SCTP. The handover scheme being proposed employs an aggressive polling of all destination addresses within an individual SCTP association in order to determine the round trip delay to each of these addresses. It then performs handover based on these measured path delays. This delay-centric approach does not incur the penalty associated with the current failover-based scheme, namely a number of timeouts before handover is performed. In some cases the proposed scheme can actually preempt the path failure, and perform handover before it occurs. The proposed scheme has been evaluated through simulation, emulation, and within the context of a wireless environment

    End-to-end mobility for the internet using ILNP

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    This work was partially funded by the Government of Thailand through a PhD scholarship for Dr Phoomikiattisak.As the use of mobile devices and methods of wireless connectivity continue to increase, seamless mobility becomes more desirable and important. The current IETF Mobile IP standard relies on additional network entities for mobility management, can have poor performance, and has seen little deployment in real networks. We present a host-based mobility solution with a true end-to-end architecture using the Identifier-Locator Network Protocol (ILNP). We show how the TCP code in the Linux kernel can be extended allowing legacy TCP applications that use the standard C sockets API to operate over ILNP without requiring changes or recompilation. Our direct testbed performance comparison shows that ILNP provides better host mobility support than Mobile IPv6 in terms of session continuity, packet loss, and handoff delay for TCP.Publisher PDFPeer reviewe

    SIGMA: A mobility architecture for terrestrial and space networks.

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    Internet Protocol (IP) mobility can be handled at different layers of the protocol stack. Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP suffers from a number of drawbacks such as the requirement for infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. As an alternative solution, a few transport layer mobility protocols have been proposed in the context of Transmission Control Protocol (TCP), for example, MSOCKS and TCP connection migration. In this dissertation, a S&barbelow; eamless I&barbelow; P-diversity-based G&barbelow; eneralized M&barbelow; obility Architecture (SIGMA) is described. SIGMA works at the transport layer and utilizes IP diversity to achieve seamless handover, and is designed to solve many of the drawbacks of Mobile IP. It can also cooperate with normal IPv4 or IPv6 infrastructure without the support of Mobile IP. The handover performance, signaling cost, and survivability issues of SIGMA are evaluated and compared with those of Mobile IP. A hierarchical location management scheme for SIGMA is developed to reduce the signaling cost of SIGMA, which is also useful to other transport layer mobility solutions. SIGMA is shown to be also applicable to managing satellite handovers in space. Finally, the interoperability between SIGMA and existing Internet security mechanisms is discussed

    Media independent handovers : network selection for mobile IP nodes in heterogeneous wireless networks

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    Includes abstract.Includes bibliographical references (p. 79-82).In Next Generation Networks (NGN), also known as 4G, Beyond 3G, Converged, Integrated and Interworked Network, user node mobility in wireless and wired environments will seamlessly cross disparate network boundaries. The effort to offer ubiquitous computing, providing access to services anywhere and anytime, strongly encourages the ability to roam across the different existing and future networks. Literature shows investigation of concepts such as Always Best Connected (ABC) when heterogeneous networks co-exist , which will work or compete with other schemes like Home Network Default (HND), Compatibility and Network Operator Agreements (CNOA) to guide network selection or access . With the variety of available networks, the mobile node may be faced with having to decide which network to connect to. We concentrate on the network selection aspects of these envisaged mobile, overlay and integrated environment in heterogeneous networks. The standard developments by the IEEE802.21 Working group and the IETF Networking group form the base of our approach that seeks to see mobility across heterogeneous networks a reality. We propose an IEEE802.21 Media Independent Handover Function (MIHF) based network discovery and network selection, leading to a handover. The selection may be further assisted by an MIHF capable Broker Node that is Third party to the Network Providers to provide a central yet distributed database of the available networks as encountered by the Mobile Node, to cater for Nodes with no prior knowledge of networks and software repository. A Mobile Node (MN) in our solution uses 802.21 communication messages to obtain information about foreign networks encountered before selecting the networks to connect to. Our evaluation through simulations, shows that network selection in heterogeneous wireless networks environment for the appropriately equipped devices is greatly enhanced by the use of the Media Independent Handover Protocol. In scenarios where the mobile node has no prior knowledge of the encountered different network architectures, the use of a Broker node can, for an optimal number of available networks also greatly enhance the mobile node’s network selection by reducing the delay associated and the packet losses incurred

    Avaliação de controlo de sessÔes multicast em redes com contexto

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    Mestrado em Engenharia ElectrĂłnica e TelecomunicaçÔesOs utilizadores pretendem aceder, cada vez mais, a serviços multimĂ©dia com requisitos mais exigentes e personalizados. As limitaçÔes impostas pelos ambientes existentes (internet, 3G) para fornecer estes serviços levam Ă  procura de melhores soluçÔes, nomeadamente uma gestĂŁo eficaz das sessĂ”es multiparty. Neste tipo de soluçÔes Ă© normalmente utilizado o multicast, jĂĄ que este permite reduzir os recursos utilizados, diminuindo o nĂșmero de pacotes na rede. Contudo, o multicast nĂŁo estĂĄ consistente ao nĂ­vel dos cenĂĄrios de mobilidade, fundamentais nas redes de prĂłxima geração. Actualmente existe uma vasta gama de tecnologias de acesso sem fios como WiFi, GPRS, UMTS e WiMAX. No futuro estas tecnologias diferentes complementar-se-ĂŁo convergindo numa infra-estrutura heterogĂ©nea capaz de fornecer um melhor serviço aos utilizadores, denominadas de redes 4G. A evolução dos terminais mĂłveis tambĂ©m permitirĂĄ que estes se liguem simultaneamente a vĂĄrias redes de acesso. Para uma melhor distribuição dos serviços dos utilizadores pelas redes de acesso disponĂ­veis sĂŁo necessĂĄrios novos mecanismos de selecção. Uma nova selecção da rede baseada em informação de contexto (entidades e ambiente) tem tido grande relevo na comunidade cientĂ­fica. Assim, aplicaçÔes e rede reagem a alteraçÔes de contexto para uma melhor selecção da mesma. A dissertação apresentada encontra-se no Ăąmbito do transporte multiparty com informação de contexto e reserva de recursos, permitindo a entrega do conteĂșdo de uma forma personalizada e com Qualidade de Serviço a vĂĄrios utilizadores mĂłveis, independentemente da tecnologia de acesso de cada um e da prĂłpria tecnologia da rede. Em suma, Ă© utilizada uma arquitectura de rede baseada em informação de contexto e que reage eficazmente a alteraçÔes do mesmo. De forma a implementar a proposta apresentada recorreu-se Ă  criação de vĂĄrias entidades no simulador de redes NS-2. Os resultados foram obtidos usando diferentes cenĂĄrios, avaliando a influĂȘncia de cada parĂąmetro individualmente. Demonstrou-se que a arquitectura implementada permite suportar uma entrega dos conteĂșdos de uma maneira personalizada e independente da tecnologia utilizada. Obteve-se ainda uma boa gestĂŁo dos recursos da rede e uma melhoria na experiĂȘncia percepcionada pelo utilizador atravĂ©s da selecção total da rede com base numa entidade de controlo central. A introdução do overlay de transporte multiparty melhora o comportamento geral da rede, minimizando as reconfiguraçÔes frequentes necessĂĄrias.Nowadays, more and more users want to access multimedia services with strong and personalized requirements. The limitations intrinsic to current environments (Internet and 3G) to provide this type of services motivate the research for an efficient management of multiparty sessions. The solution can also be based on multicast implementation, since it reduces resources utilization, decreasing the number of packets in the network. However, current multicast is not a strong solution in mobility scenarios, essential in next generation networks. Currently there is a wide range of wireless access technologies such as WiFi, GPRS, UMTS and WiMAX. In the future, these different technologies will converge in a complementary manner forming a heterogeneous infrastructure able to offer a better service to its users, usually named 4G. The evolution of mobile terminals will also allow them to connect simultaneously to several access networks. In order to a better distribution of the users services throughout available access networks, new selection mechanisms are required. A new network selection based on context information (entities and environments) is having a relevant role in scientific community. So, applications and networks react according to context changes, improving network selection. This Thesis is in the scope of context-aware multiparty transport with resources allocation, allowing the delivery of content in a personalized way with Quality of Service to several users, independently of the technology and the network. Resuming, the solution implements a context-aware network architecture that reacts efficiently to its changes. In order to implement this architecture, new entities were created in the network simulator NS-2. The results were obtained using different scenarios, evaluating the influence of each parameter independently. It was demonstrated that the integration of several components, allows a delivery of contents in a personalized manner and independently of the technology. The results showed a better management of the network resources and users experience, throughout the total network selection, based on a central control unit. The multiparty transport overlay improves the network behaviour, minimizing the necessary frequent reconfigurations
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