Mobility and service discovery in opportunistic networks

Service discovery and selection approaches are often done using a centralized registry-based technique, which only captures common Quality of Service criteria. With more and more services offered via social networks, these approaches are not able to evaluate trust in service providers and often fail to comply with new requester's expectations. This is because theses approaches are not able (i) to take into consideration the social dimension and (ii) to capitalize on information resulting from previous experiences. To address these challenges, we propose the use of multi-agent systems as they have demonstrated the capability to use previous interactions, knowledge representation and distributed reasoning, as well as social metaphors like trust. More precisely, in this paper, we enhance service discovery and selection processes by integrating the societal view in trust modeling. Based on relationships between agents, their previous experiences and extracted information from social network, we define a trust model built upon social, expert and recommender-based components. The social-based component judges whether the provider is worthwhile pursuing before using his services (viz. trust in sociability). The expert-based component estimates whether the service behaves well and as expected (viz. trust in expertise). The recommender-based component assesses for an agent whether one's can rely on its recommendations (viz. trust in recommendation). However, when searching for a service in a social network, agents (service requester and service providers) may have no direct interactions or previous experiences. This requires a method to infer trust between them. Based on a probabilistic model, we estimate trust between non adjacent agents while taking into account roles (recommender or provider) of intermediate agents. Moreover, we propose a distributed algorithm for trustworthy service discovery and selection using referral systems in social networks. Experiments demonstrate that our approach is effective and outperforms existing ones, and can deliver more trustworthy results.

This paper concerns network and service discovery problems in heterogeneous broadcast environment. Broadcasting has traditionally been limited to single network type. The future broadcasting landscape will be composed of different type of networks, especially the mobile broadcast networks like DVB-H, DMB, WLAN, WiMAX and 3G MBMS. Integration of these networks into a unified broadcast infrastructure requires extensions to the current network and service discovery methods. Existing methods are limited to a single network type which makes them cumbersome. There is a possibility to considerably improve this process by unifying the network and service discovery across different broadcast networks. The process can also be helped by utilizing location databases. In this paper, we propose a Universal Network and Service Discovery (UNSD) system and positioning information system which provides discovery support for many different network types and inclusion of positioning information.

An increasing number of mobile users (MUs) share common interests in general information, such as traffic information, weather forecast, and domestic/international news. However, the centralized infrastructure-based system has not been designed for efficiently disseminating the information of common interest (IoCI) to numerous requesters. Thanks to the rapid development of mobile devices equipped with large storage and multiple communication modes, opportunistic communication between a pair of MUs can be readily realized. With the aid of opportunistic networks formed by MUs, we can improve the connectivity of cellular networks in the rural areas, we can offload the tele-traffic from the overloaded cellular networks, and we can efficiently disseminate the IoCI in the densely populated areas. We commence with a detailed survey on the cross-disciplinary research area of social network analysis aided telecommunication networking. We continue by focusing our attention on the family of integrated cellular and large-scale opportunistic networks, whose performance is dominated by the inter-contact duration as well as the contact duration between any pairs of MUs. A continuous-time-pure-birth Markov chain is invoked for analyzing the relevant performance. We demonstrate that the delivery ratio of the IoCI before it expires becomes higher than 90% with the aid of opportunistic networks consisting of 20 MUs. Moreover, our experiments based on the InfoCom 2006 mobility trace show that the opportunistic networks are capable of offloading 58% of the tele-traffic from the cellular networks. Thereafter, we propose a hybrid information dissemination scheme for the integrated cellular and small-scale opportunistic networks, which is comprised of two main stages: 1) the base station-aided single-hop multicast (BSSHM) stage and 2) the cooperative multicast aided spontaneous dissemination stage. In contrast to their large-scale counterparts, in small-scale opportunistic networks, the information dissemination is mainly affected by the mobility of the MUs, by the wireless channel attenuation and by the resource scheduling, where a discrete-time-pure-birth Markov chain is utilized for characterizing the relevant performance. We demonstrate that our hybrid information dissemination scheme outperforms the traditional BSSHM in terms of various delay metrics, despite consuming less energy.

Designed as a specialized ad hoc network suitable for applications such as emergency responses, OppNets are considered as a sub-class of DTN where communication opportunities are intermittent, so an end-to-end path between the source and the destination may never exist. Existing networks have already brought connectivity to a broad range of devices, such as hand held devices, laptops, tablets, PC, etc. The Internet of Things (IoT) will extend the connectivity to devices beyond just mobile phones and laptops, but to buildings, wearable devices, cars, different things and objects. There are different issues for these networks. One of them is the selection of IoT nodes in order to carry out a task in opportunistic networks. In this work, we implement a Fuzzy-Based System for IoT node selection in opportunistic networks. For our proposed system, we use four input parameters: IoT Node’s Unique Encounters (NUE), IoT Node’s Free Buffer Space (NFBS), IoT Node’s Batter Level (NBL) and IoT Node Contact Duration (NCD). The output parameter is IoT Node Selection Decision (NSD). The results show that the proposed system makes a proper selection decision of IoT nodes in opportunistic networks. The IoT node selection is increased up to 25% and 11% by increasing NCD and NUE, respectively.

We investigated performance of localized distance-sensitive service discovery algorithm iMesh, which generates information structure in static network, to store the information about nearby actors (service providers). In a network with grid structure, this is achieved by advertising service provider positions in four geographical directions. The propagation of information about remote service providers is restricted by a blocking rule, to reduce the message overhead and provide distance sensitivity. A node requiring service (service consumer) conducts lookup process to obtain information about nearby service providers from the iMesh structure. We modified iMesh to enable its use in dense networks with topologies other than grid by introducing iMesh areas instead of iMesh edges. Our simulations compare performance of modified iMesh with another localized service discovery scheme (quorum) in dense networks with random topologies. We show that iMesh finds the nearest service provider in >95% of cases. It significantly decreases the message overhead compared to quorum, without compromising quality of service discovery.

Sensor network is a novel technology about acquiring and processing information. This paper introduces the basic interaction patterns between requesters and providers of services during a typical Service Discovery task. It discusses existing service discovery protocols and provides a preliminary analysis of the mechanisms for service and resource discovery in the Wireless Sensor Network domain.

Opportunistic networks are usually formed spontaneously by mobile devices equipped with short range wireless communication interfaces. The idea is that an end-to-end connection may never be present. Designing and implementing a routing protocol to support both service discovery and delivery in such kinds of networks is a challenging problem on account of frequent disconnections and topology changes. In this network one of the most important issues relies on the selection of the best intermediate node to forward the messages towards the destination. This paper presents a trust framework for opportunistic network where the nodes in the network follow the trace based mobility model. The selection of next hop to forward the data packets is based on the trust value as well as the direction of movement of node towards the destination. The trust value is obtained from the trust framework of the data forwarding node. The direction of destination is obtained from the movement trace file that is maintained by the nodes in the network. In this proposed framework, the message is encrypted to secure both the data and path information. The effectiveness of this proposed framework is shown using simulation.

With the maturation of wireless networks technologies, Telematics service is becoming a new rising and popular network service and application. In this paper, a centralized vehicular Peer-to-Peer Telematics (C-VP2P) service discovery platform is proposed to provide efficient and feasible service discovery. This paper focuses on the issues of developing a Telematics service platform over the vehicular network environment. When a user needs a service on the road, two issues need to be considered: (1) how to have the candidate list of service providers? (2) how to select suitable service providers from the candidate list? In order to tackle these two issues, we propose a C-VP2P-based system service discovery mechanism using the vehicular P2P messaging protocol. In this paper, the vehicular P2P messaging protocol is designed to communicate among Telematics central server, clients and service providers. In addition, a service discovery mechanism in the C-VP2P system is proposed to achieve high precision discovery for service providers. We also exhibit the performance merits of the proposed C-VP2P Telematics service discovery platform in this paper.

In this paper, an agent-based cross-layer secure service discovery scheme has been presented. Service discovery in MANET is a critical task and it presents numerous security challenges. These threats can compromise the availability, privacy and integrity of service discovery process and infrastructure. This paper highlights various security challenges prevalent to service discovery in MANET. Then, in order to address these security challenges, the paper proposes a cross-layer, agent based secure service discovery scheme for MANET based on deep neural network. The software agents will monitor the intrusive activities in the network based on an Intrusion Detection System (IDS). The service discovery operation is performed based on periodic dissemination of service, routing and security information. The QoS provisioning is achieved by encapsulating QoS information in the periodic advertisements done by service providers. The proposed approach has been implemented in JIST/ SWANS simulator. The results show that proposed approach provides improved security, scalability, latency, packet delivery ratio and service discovery success ratio, for various simulation scenarios.

Service Discovery (SD) is an integral part of service networks. Before a service can be used, it needs to be discovered successfully. Thus, a comprehensive service dependability analysis needs to consider the dependability of the SD process. As a time-critical operation, an important property of SD is responsiveness: the probability of successful discovery within a deadline, even in the presence of faults. This is especially true for dynamic networks with complex fault behavior such as wireless networks. We present results of a comprehensive responsiveness evaluation of decentralized SD, specifically active SD using the Zeroconf protocol. The ExCovery experiment framework has been employed in the Distributed Embedded System (DES) wireless test bed at Freie Universitat Berlin. We present and discuss the experiment results and show how SD responsiveness is affected by the position and number of requesters and providers as well as the load in the network. Results clearly demonstrate that in all but the most favorable conditions, the configurations of current SD protocols struggle to achieve a high responsiveness. We further discuss results reflecting the long-term behavior of the test bed and how its varying reliability impacts SD responsiveness.

This paper presents our work towards a fully functioning platform for pervasive service engineering in an operational support services (OSS) context for an ICT service provider. The focus of the paper lies in a proof-of-concept for a novel means to develop and execute pervasive services, with simplicity and maintainability as prime drivers. The essence of this approach is the novel integration of the policy-based management (PBM) techniques and the model-driven architecture (MDA) techniques for specifying pervasive services and their behaviour, together with auto-generation of middleware implementation and policy enablement. The presence of policies provides pervasive services with the high flexibility and adaptability needed for dealing with changing environments and resource availabilities, while the introduction of MDA for defining pervasive service information models fundamentally solves the information modelling puzzle of current policy-based approaches. Additionally, MDA’s middleware-neutral feature benefits the smooth evolution of pervasive services as a piece of software artefact in the face of heterogeneous devices and platforms. A preliminary case study has demonstrated the practical feasibility and benefits of this approach. The case study revolves around an ICT service called TEANU — transparent enterprise access for nomadic user. The service provides a means for nomadic users to maintain a secure access to their enterprise network in the presence of multiple access network providers with different service level guarantees.

Intelligent Transportation Systems (ITS) are gaining momentum among researchers. ITS encompasses several technologies, including wireless communications, sensor networks, data and voice communication, real-time driving assistant systems, etc. These states of the art technologies are expected to pave the way for a plethora of vehicular network applications. In fact, recently we have witnessed a growing interest in Vehicular Networks from both the research community and industry. Several potential applications of Vehicular Networks are envisioned such as road safety and security, traffic monitoring and driving comfort, just to mention a few. It is critical that the existence of convenience or driving comfort services do not negatively affect the performance of safety services. In essence, the dissemination of safety services or the discovery of convenience applications requires the communication among service providers and service requesters through constrained bandwidth resources. Therefore, service discovery techniques for vehicular networks must efficiently use the available common resources. In this thesis, we focus on the design of bandwidth-efficient and scalable service discovery protocols for Vehicular Networks. Three types of service discovery architectures are introduced: infrastructure-less, infrastructure-based, and hybrid architectures. Our proposed algorithms are network layer based where service discovery messages are integrated into the routing messages for a lightweight discovery. Moreover, our protocols use the channel diversity for efficient service discovery. We describe our algorithms and discuss their implementation. Finally, we present the main results of the extensive set of simulation experiments that have been used in order to evaluate their performance.

SummaryOpportunistic network applications are usually assumed to work only with unordered immutable messages, like photos, videos, or music files, while applications that depend on ordered or mutable messages, like chat or shared contents editing applications, are ignored. In this paper, we examine how total ordering can be achieved in an opportunistic network. By leveraging on existing dissemination and causal order algorithms, we propose a commutative replicated data type algorithm on the basis of Logoot for achieving total order without using tombstones in opportunistic networks where message delivery is not guaranteed by the routing layer. Our algorithm is designed to use the nature of the opportunistic network to reduce the metadata size compared to the original Logoot, and even to achieve in some cases higher hit rates compared to the dissemination algorithms when no order is enforced. Finally, we present the results of the experiments for the new algorithm by using an opportunistic network emulator, mobility traces, and Wikipedia pages.

In this paper we propose the design and implementation of ServBGP, a service routing protocol for managing service collaboration among cloud providers in cloud computing. ServBGP is based on the policy-driven design of the well-known BGP Internet routing protocol to support the different service interaction models currently employed in the cloud particularly the monolithic, composite, and broker-based service models. The main contribution of this work lies in devising a system that autonomously manages the different aspects of service interaction and collaboration among service providers from service discovery and advertisement to service consumption and revocation. The ServBGP routing decision engine is planned to operate by processing cost-bidding and QoS advertisement messages from the different cloud providers. A proof of concept implementation of the ServBGP design is realized on the NetKit network emulation and virtualization platform using the standard BGPv4 protocol specification.

Service discovery is an integral part of Mobile Ad Hoc Networks (MANETs). While several service discovery protocols such as Service Location Protocol [1] and Universal Plug and Play (UPnP)[2] have been developed, most of them are designed for infrastructure based networks and thus not suitable to be used in MANETs. This paper proposes Mobile Agent Based Service Discovery (MASD) for Ad Hoc network. It is a policy driven agent based mechanism that facilitates cross platform service discovery in ad-hoc environments. The various agents are chosen in MASD which executes the predefined policies. Our approach achieves a high degree of flexibility in adapting itself to changes in ad-hoc environments and is aware of common problems associated with structured compound formation in mobile Ad Hoc environments. Mechanism consists of grouping mobile nodes into clusters while a gateway in each cluster is responsible for routing. We evaluated the performance of the scheme by running simulations on Glomosim simulator. Also the motion of agents is taken care of by PMADE (Platform for Mobile Agent Distribution and Execution).The results obtained shows that MASD is quite effective for successful service discovery in MANETs.