2014. 3rd issue
Full issue (12 MB)
SPECIAL ISSUE ON FUTURE INTERNET, PART I.
Gy. Sallai, W. Schreiner, and J. Sztrik
Special Issue on the Future Internet – GUEST EDITORIAL
Recent dramatic changes such as the rising number of Internet users, the penetration of portable and mobile devices, or the Internet of Things, has motivated a number of research initiatives, labeled "Future Internet" worldwide, supported by NSF in the USA and EU research framework programs in Europe. In Hungary, the ongoing "Future Internet Research, Services and Technology – FIRST" project, supported by the European Social Funds focuses on key theoretical, modeling, planning, application and experimental aspects of Future Internet. The six papers published in this special issue demonstrate the research results achieved by the FIRST research community in various fields related to Future Internet....
Z. Móczár and S. Molnár
Towards the Transport Protocols of Future Internet
End-to-end congestion control performed by the Transmission Control Protocol (TCP) is the main data transfer mechanism of today's Internet providing reliable communication between hosts. Since the deployment of TCP the Internet has gone through a significant change due to the evolving network technologies and the diversity of applications. This process has led to a heterogeneous environment with complex traffic characteristics raising the demand for working out different TCP versions to achieve better performance in various network conditions. In addition to the traditional congestion control scheme several alternative solutions have also been proposed for reliable transport. However, the current practice of continuous modification and refinement of TCP for specific network environments does not seem to be a viable option, hence there is an increasing need for a more efficient and flexible transport protocol. In this paper we present a survey of the major data transfer mechanisms developed in the last decades, and advocate a possible direction for future research.
A. Kuki, B. Almási, T. Bérczes, and J. Sztrik
Modeling a QoS Classified Communication in a Multiuser Wi-Fi Environment
The aim of the present paper is to propose a finite source queueing model in order to include the random backoff feature of the wireless communication. Two classes of sources (high priority and low priority traffic) are included. The random backoff feature is implemented by using retrial queues for each traffic class. Supposing exponentially distributed interevent times the MOSEL software tool is used to develop the special software to calculate the most important steady-state performance characteristics of the system, such as utilizations, mean orbit sizes, mean waiting times, that is mean time spent in the orbit. It is showed how the retrial discipline effects the mean waiting times (compared to the FIFO discipline): not only the values, but also the form of the curve is quite different in the case of packet reordering.
L. Bokor, G. Jeney, and J. Kovács
A Study on the Performance of an Advanced Framework for Prediction-based NEMO Handovers in Multihomed Scenarios
In this paper we provide an extensive performance evaluation of an already introduced advanced handover management solution which aimed at providing ubiquitous IPv6 connection and seamless Internet access for network mobility (NEMO) scenarios. The novel solution makes use of geographic location information and previous records of access network parameters. The method exploits the benefits of multihomed mobility configurations by introducing a special handover execution protocol entirely based on flow bindings. Using actual location information and previously recorded con-text data, the system is able to predict handovers and proactively prepare itself for the appearance of access networks. We studied the performance of our proposal by implementing the framework and handover execution scheme in a real-life 3G/Wi-Fi multi-access testbed environment, and showed that handover latency is almost totally eliminated. As our solution strongly relies on the prediction accuracy, we have also developed a probabilistic system model and evaluated of the probability of wrong posi-tioning on the prediction raster.
P. Orosz, T. Skopkó, and M. Varga
RCTP: A Low-complexity Transport Protocol for Collecting Measurement Data
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are the essential transport protocols of the Internet Protocol (IP) networks. Both of them are dedicated for certain purposes and face their obvious limitations. Thus, there is a constant endeavor for developing alternatives. Despite the reliability feature of TCP, its relatively high complexity does not always enable to implement it in a hardware environment with constrained resources. Our paper introduces a low-complexity transport protocol dedicated to a real-time network monitoring system operating at 10+ Gbps. Its task is to transport the preprocessed IP packets from the monitoring device to the post-processing hosts without loss over a dedicated LAN. Resource requirement on sender side has to be reduced as much as possible while trying to maintain high throughput. Although RCTP is intended to serve in a network measurement system, it may be suitable for other measurement infrastructures such as sensor networks, where data provided by the sensors with limited resources have to be collected at a central node.
Z. Gál, B. Almási, T. Dabóczi, R. Vida, S. Oniga, S. Baran, and I. Farkas
Internet of Things: Application Areas and Research Results of the FIRST Project
The FIRST/IoT project coordinated by the Faculty of Informatics, University of Debrecen, Hungary has important impact on the R&D work in this field. Six activity areas have been covered in the twenty-seven months long project. More than thirty researchers from half dozen Hungarian and other universities and research institutes have been involved in this activity. The results of this work are planned to be used for other international IoT projects in the following time period. Other institutes and individual researchers from abroad are invited to join to this open initiative and become partner. In the paper are presented the results an
G. Kocsis and I. Varga
Investigation of Spreading Phenomena on Social Networks
In this paper the results of our investigations related to social spreading are summed up and concluded. In our work we studied information spreading on different network topologies. Based on a novel complex network generating method we managed to generate several test cases for social simulations focusing mainly on the case of declining social networks. We ran simulations using a previously presented model of information spreading. As a result we showed how the effectiveness of the spreading depends on the way and the intensity of declining. Later, using a modified version of the model we examined the effect of dynamically active agents in the system. As the most important result of this study we showed that increasing the activity of central nodes of a social network alone does not make the spreading significantly more effective.
PAPERS FROM OPEN CALL
L. Chiariglione and Cs. A. Szabó
Multimedia Communications: Technologies, Services, Perspectives Part II. Applications, Services and Future Directions
This survey/position paper gives an overview of the state-of-the art multimedia communications technologies and services, analyses their present significance and expected future role, and attempts to identify development trends. The paper analyses the evolution of networking infrastructure and multi-media services over the last decade and identifies future direc-tions. It consists of two parts. Part I, published in the preceding issue of this journal, dealt with the technologies and systems for multimedia delivery, and covered the dedicated networks such as digital broadcasting systems and IPTV and the technologies of Internet based multimedia delivery. The present paper, Part II, addresses applications, services and future directions.