1,726 research outputs found

    A Survey on Handover Management in Mobility Architectures

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    This work presents a comprehensive and structured taxonomy of available techniques for managing the handover process in mobility architectures. Representative works from the existing literature have been divided into appropriate categories, based on their ability to support horizontal handovers, vertical handovers and multihoming. We describe approaches designed to work on the current Internet (i.e. IPv4-based networks), as well as those that have been devised for the "future" Internet (e.g. IPv6-based networks and extensions). Quantitative measures and qualitative indicators are also presented and used to evaluate and compare the examined approaches. This critical review provides some valuable guidelines and suggestions for designing and developing mobility architectures, including some practical expedients (e.g. those required in the current Internet environment), aimed to cope with the presence of NAT/firewalls and to provide support to legacy systems and several communication protocols working at the application layer

    Towards zero packet loss with LISP Mobile Node

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    Host mobility protocols such as Locator-Identifier Separation Protocol Mobile Node (LISP-MN) are known to experience packet loss at the point of handover. For the duration of the handover, packets sent to the MN via the old access link are dropped by the router since it has no way of knowing where the device has moved to. This affects the performance of transport layer protocols of the TCP/IP stack, which results in degradation of network performance. Buffering these packets close to the MN's new location and forwarding them to the MN on handover completion is one way of improving the overall performance of the mobility protocol. Hence, we introduce a novel network node, loc-server, to buffer these packets in order to mitigate the packet loss and reduce the service disruption time (SDT) experienced by MNs during handovers. Using a laboratory testbed implementation, LISP-MN with loc-server support shows significant reduction in packet loss and reduced SDT in comparison to vanilla LISP-MN. Similarly, performance analysis of DASH video player also shows the new architecture helps in improving the average video quality downloaded by the MN and reduces the player's instability

    Inter-domain mobility with LISP-MN:a performance comparison with MIPv6

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    In this work, we aim to evaluate Locator Identifier Separation Protocol-Mobile Node (LISP-MN) performance in an inter-domain mobility scenario for both multi-interface and single interface MN with focus on throughput, handover delay, service disruption time and packet loss. To serve as the benchmark for performance, we compare LISP-MN with the IETF standardised MIPv6. We implement the 2 protocols on a laboratory testbed comprising all the nodes necessary for their operation. For multi-interface MNs, LISP-MN shows a better response in soft handover scenarios in terms of throughput and packet loss. MIPv6 on the other hand shows shorter handover delay with lower service disruption time in a hard handover scenario. Both protocols demonstrate poor performance for a single interface MN due to the long handover delay experienced. Although LISP-MN’s handover control messages doubled that of MIPv6, our experiments show that it takes a similar time as MIPv6 to complete the handover message exchange

    Using XML and XSLT for flexible elicitation of mental-health risk knowledge

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    Current tools for assessing risks associated with mental-health problems require assessors to make high-level judgements based on clinical experience. This paper describes how new technologies can enhance qualitative research methods to identify lower-level cues underlying these judgements, which can be collected by people without a specialist mental-health background. Methods and evolving results: Content analysis of interviews with 46 multidisciplinary mental-health experts exposed the cues and their interrelationships, which were represented by a mind map using software that stores maps as XML. All 46 mind maps were integrated into a single XML knowledge structure and analysed by a Lisp program to generate quantitative information about the numbers of experts associated with each part of it. The knowledge was refined by the experts, using software developed in Flash to record their collective views within the XML itself. These views specified how the XML should be transformed by XSLT, a technology for rendering XML, which resulted in a validated hierarchical knowledge structure associating patient cues with risks. Conclusions: Changing knowledge elicitation requirements were accommodated by flexible transformations of XML data using XSLT, which also facilitated generation of multiple data-gathering tools suiting different assessment circumstances and levels of mental-health knowledge

    State-of-the-Art Multihoming Protocols and Support for Android

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    Il traguardo più importante per la connettività wireless del futuro sarà sfruttare appieno le potenzialità offerte da tutte le interfacce di rete dei dispositivi mobili. Per questo motivo con ogni probabilità il multihoming sarà un requisito obbligatorio per quelle applicazioni che puntano a fornire la migliore esperienza utente nel loro utilizzo. Sinteticamente è possibile definire il multihoming come quel processo complesso per cui un end-host o un end-site ha molteplici punti di aggancio alla rete. Nella pratica, tuttavia, il multihoming si è rivelato difficile da implementare e ancor di più da ottimizzare. Ad oggi infatti, il multihoming è lontano dall’essere considerato una feature standard nel network deployment nonostante anni di ricerche e di sviluppo nel settore, poiché il relativo supporto da parte dei protocolli è quasi sempre del tutto inadeguato. Naturalmente anche per Android in quanto piattaforma mobile più usata al mondo, è di fondamentale importanza supportare il multihoming per ampliare lo spettro delle funzionalità offerte ai propri utenti. Dunque alla luce di ciò, in questa tesi espongo lo stato dell’arte del supporto al multihoming in Android mettendo a confronto diversi protocolli di rete e testando la soluzione che sembra essere in assoluto la più promettente: LISP. Esaminato lo stato dell’arte dei protocolli con supporto al multihoming e l’architettura software di LISPmob per Android, l’obiettivo operativo principale di questa ricerca è duplice: a) testare il roaming seamless tra le varie interfacce di rete di un dispositivo Android, il che è appunto uno degli obiettivi del multihoming, attraverso LISPmob; e b) effettuare un ampio numero di test al fine di ottenere attraverso dati sperimentali alcuni importanti parametri relativi alle performance di LISP per capire quanto è realistica la possibilità da parte dell’utente finale di usarlo come efficace soluzione multihoming

    An integrated security Protocol communication scheme for Internet of Things using the Locator/ID Separation Protocol Network

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    Internet of Things communication is mainly based on a machine-to-machine pattern, where devices are globally addressed and identified. However, as the number of connected devices increase, the burdens on the network infrastructure increase as well. The major challenges are the size of the routing tables and the efficiency of the current routing protocols in the Internet backbone. To address these problems, an Internet Engineering Task Force (IETF) working group, along with the research group at Cisco, are still working on the Locator/ID Separation Protocol as a routing architecture that can provide new semantics for the IP addressing, to simplify routing operations and improve scalability in the future of the Internet such as the Internet of Things. Nonetheless, The Locator/ID Separation Protocol is still at an early stage of implementation and the security Protocol e.g. Internet Protocol Security (IPSec), in particular, is still in its infancy. Based on this, three scenarios were considered: Firstly, in the initial stage, each Locator/ID Separation Protocol-capable router needs to register with a Map-Server. This is known as the Registration Stage. Nevertheless, this stage is vulnerable to masquerading and content poisoning attacks. Secondly, the addresses resolving stage, in the Locator/ID Separation Protocol the Map Server (MS) accepts Map-Request from Ingress Tunnel Routers and Egress Tunnel Routers. These routers in trun look up the database and return the requested mapping to the endpoint user. However, this stage lacks data confidentiality and mutual authentication. Furthermore, the Locator/ID Separation Protocol limits the efficiency of the security protocol which works against redirecting the data or acting as fake routers. Thirdly, As a result of the vast increase in the different Internet of Things devices, the interconnected links between these devices increase vastly as well. Thus, the communication between the devices can be easily exposed to disclosures by attackers such as Man in the Middle Attacks (MitM) and Denial of Service Attack (DoS). This research provided a comprehensive study for Communication and Mobility in the Internet of Things as well as the taxonomy of different security protocols. It went on to investigate the security threats and vulnerabilities of Locator/ID Separation Protocol using X.805 framework standard. Then three Security protocols were provided to secure the exchanged transitions of communication in Locator/ID Separation Protocol. The first security protocol had been implemented to secure the Registration stage of Locator/ID separation using ID/Based cryptography method. The second security protocol was implemented to address the Resolving stage in the Locator/ID Separation Protocol between the Ingress Tunnel Router and Egress Tunnel Router using Challenge-Response authentication and Key Agreement technique. Where, the third security protocol had been proposed, analysed and evaluated for the Internet of Things communication devices. This protocol was based on the authentication and the group key agreement via using the El-Gamal concept. The developed protocols set an interface between each level of the phase to achieve security refinement architecture to Internet of Things based on Locator/ID Separation Protocol. These protocols were verified using Automated Validation Internet Security Protocol and Applications (AVISPA) which is a push button tool for the automated validation of security protocols and achieved results demonstrating that they do not have any security flaws. Finally, a performance analysis of security refinement protocol analysis and an evaluation were conducted using Contiki and Cooja simulation tool. The results of the performance analysis showed that the security refinement was highly scalable and the memory was quite efficient as it needed only 72 bytes of memory to store the keys in the Wireless Sensor Network (WSN) device

    Research and applications: Artificial intelligence

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    The program is reported for developing techniques in artificial intelligence and their application to the control of mobile automatons for carrying out tasks autonomously. Visual scene analysis, short-term problem solving, and long-term problem solving are discussed along with the PDP-15 simulator, LISP-FORTRAN-MACRO interface, resolution strategies, and cost effectiveness

    Virtual Mobility Domains - A Mobility Architecture for the Future Internet

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    The advances in hardware and wireless technologies have made mobile communication devices affordable by a vast user community. With the advent of rich multimedia and social networking content, an influx of myriads of applications, and Internet supported services, there is an increasing user demand for the Internet connectivity anywhere and anytime. Mobility management is thus a crucial requirement for the Internet today. This work targets novel mobility management techniques, designed to work with the Floating Cloud Tiered (FCT) internetworking model, proposed for a future Internet. We derive the FCT internetworking model from the tiered structure existing among Internet Service Provider (ISP) networks, to define their business and peering relationships. In our novel mobility management scheme, we define Virtual Mobility Domains (VMDs) of various scopes, that can support both intra and inter-domain roaming using a single address for a mobile node. The scheme is network based and hence imposes no operational load on the mobile node. This scheme is the first of its kind, by leveraging the tiered structure and its hierarchical properties, the collaborative network-based mobility management mechanism, and the inheritance information in the tiered addresses to route packets. The contributions of this PhD thesis can be summarized as follows: · We contribute to the literature with a comprehensive analysis of the future Internet architectures and mobility protocols over the period of 2002-2012, in light of their identity and handoff management schemes. We present a qualitative evaluation of current and future schemes on a unified platform. · We design and implement a novel user-centric future Internet mobility architecture called Virtual Mobility Domain. VMD proposes a seamless, network-based, unique collaborative mobility management within/across ASes and ISPs in the FCT Internetworking model. The analytical and simulation-based handoff performance analysis of the VMD architecture in comparison with the IPv6-based mobility protocols presents the considerable performance improvements achieved by the VMD architecture. · We present a novel and user-centric handoff cost framework to analyze handoff performance of different mobility schemes. The framework helps to examine the impacts of registration costs, signaling overhead, and data loss for Internet connected mobile users employing a unified cost metric. We analyze the effect of each parameter in the handoff cost framework on the handoff cost components. We also compare the handoff performance of IPv6-based mobility protocols to the VMD. · We present a handoff cost optimization problem and analysis of its characteristics. We consider a mobility user as the primary focus of our study. We then identify the suitable mathematical methods that can be leveraged to solve the problem. We model the handoff cost problem in an optimization tool. We also conduct a mobility study - best of our knowledge, first of its kind - on providing a guide for finding the number of handoffs in a typical VMD for any given user\u27s mobility model. Plugging the output of mobility study, we then conduct a numerical analysis to find out optimum VMD for a given user mobility model and check if the theoretical inferences are in agreement with the output of the optimization tool
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