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  • 1.
    Ahlgren, Bengt
    et al.
    RISE., Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Karl, Holger
    Kutscher, Dirk
    Zhang, Lixia
    Special section on Information-Centric Networking (editorial)2013Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 36Artikel i tidskrift (Refereegranskat)
  • 2.
    Badia, Leonardo
    et al.
    University of Ferrara.
    Lindström, Magnus
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Zander, Jens
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Zorzi, Michele
    University of Ferrara.
    An Economic Model For The Radio Resource Management In Multimedia Wireless Systems2004Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 27, nr 11, s. 1056-1064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we study the connection between radio resource management (RRM) and economic parameters, whose application in multimedia communication system is a challenging task. In fact, a real network provider has to consider other parameters, besides the common goals of RRM like throughput maximisation or meeting constraints connected with the quality of service. In particular, when the financial needs of the provider and the reaction of the users to prices are taken into account, economics have to be introduced in the analysis. We intend to study multimedia communication systems by including well-known economic models and reasonable considerations in the usual radio resource allocation scenario. To do this, we present a model of users' satisfaction, which considers the effects of both users' request and price paid. In this way, it is possible to investigate the relationship between the radio resource allocation and the provider revenue. Other conclusions can be derived as well, e.g. for the pricing strategy planning or the network dimensioning. Thus, we give analytical insight and numerical results, which highlight that the network management is heavily affected by the economic scenario.

  • 3.
    Bagula, Antoine B
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Hybrid routing in next generation IP networks2006Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 29, nr 7, s. 879-892Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a hybrid approach for routing flows in IP networks to achieve an optimal network configuration maximising bandwidth usage (optimality), minimising re-routing upon failure (reliability) and reducing the signalling overheads resulting from a full IP tunnelling (scalability). We formulate the routing of flows in IP networks as a service differentiated model where the IP flows are classified into high bandwidth demanding (LBD) and low bandwidth demanding (LBD) flows at the ingress of the network and handled differently into the core using a hybrid IGP+MPLS approach where the LBD flows are routed over the existing IGP paths while the HBD flows are carried over MPLS bandwidth-guaranteed tunnels. This model can be deployed in heterogenous network environments where HBD flows carrying real-time traffic and LBD flows transporting best-effort traffic are handled differently over a common transport network implementing traffic prioritization in response to natural or man-made emergencies. We consider the routing of flows within an IP domain's boundaries and evaluate the efficiency of the new routing approach under uniform and bursty traffic profiles. We apply the routing approach to compute paths for the traffic offered to a 20- and 50-node test networks. Simulation reveals that the hybrid routing approach outperforms both IGP and MPLS routing under the network conditions and test network models considered.

  • 4.
    Bellalta, Boris
    et al.
    Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona 08018, Spain.
    Bononi, Luciano
    Department of Computer Science and Engineering, University of Bologna, 40127 Bologna, Italy.
    Bruno, Raffaele
    Institute for Informatics and Telematics (IIT), Italian National Research Council (CNR), Pisa 56124, Italy.
    Kassler, Andreas
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT.
    Next generation IEEE 802.11 Wireless Local Area Networks: Current status, future directions and open challenges2016Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 75, s. 1-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new generation of Wireless Local Area Networks (WLANs) will make its appearance in the market in the forthcoming years based on the amendments to the IEEE 802.11 standards that have recently been approved or are under development. Examples of the most expected ones are IEEE 802.11aa (Robust Audio Video Transport Streaming), IEEE 802.11ac (Very-high throughput at < 6 GHz), IEEE 802.11af (TV White Spaces) and IEEE 802.11ah (Machine-to-Machine communications) specifications. The aim of this survey is to provide a comprehensive overview of these novel technical features and the related open technical challenges that will drive the future WLAN evolution. In contrast to other IEEE 802.11 surveys, this is a use case oriented study. Specifically, we first describe the three key scenarios in which next-generation WLANs will have to operate. We then review the most relevant amendments for each of these use cases focusing on the additional functionalities and the new technologies they include, such as multi-user MIMO techniques, groupcast communications, dynamic channel bonding, spectrum databases and channel sensing, enhanced power saving mechanisms and efficient small data transmissions. We also discuss the related work to highlight the key issues that must still be addressed. Finally, we review emerging trends that can influence the design of future WLANs, with special focus on software-defined MACs and the internet-working with cellular systems.

  • 5.
    Bellalta, Boris
    et al.
    Pompeu Fabra University, Barcelona, Spain.
    Vinel, Alexey
    Chatzimisios, Periklis
    Alexander Technological Educational Institute of Thessaloniki, Thessaloniki, Greece.
    Bruno, Raffaele
    Istituto di Informatica e Telematica (IIT) / Consiglio Nazionale delle Ricerche (CNR), Pisa, Italy.
    Wang, Chonggang
    InterDigital Communications, King of Prussia, PA, USA.
    Research advances and standardization activities in WLANs2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 39, s. 1-2Artikel i tidskrift (Refereegranskat)
  • 6.
    Bjurefors, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Karaliopoulos, Markourios
    Rohner, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Smith, Paul
    Theodoropoulos, George
    Gunningberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Resilience and Opportunistic Forwarding: Beyond Average Value Analysis2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 48, nr SI, s. 111-120Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Opportunistic networks are systems with highly distributed operation, relying on the altruistic cooperation of highly heterogeneous, and not always software and hardware-compatible, user nodes. Moreover, the absence of central coordination and control makes them vulnerable to malicious attacks. In this paper, we study the resilience of popular forwarding protocols to a representative set of challenges to their normal operation. These include jamming locally disturbing message transfer between nodes, hardware/software failures and incompatibility among nodes rendering contact opportunities useless, and free-riding phenomena. We first formulate and promote the metric envelope concept as a tool for assessing the resilience of opportunistic forwarding schemes. Metric envelopes depart from the standard practice of average value analysis and explicitly account for the differentiated challenge impact due to node heterogeneity (device capabilities, mobility) and attackers’ intelligence. We then propose heuristics to generate worst- and best-case challenge realization scenarios and approximate the lower and upper bounds of the metric envelopes. Finally, we demonstrate the methodology in assessing the resilience of three popular forwarding protocols in the presence of the three challenges, and under a comprehensive range of mobility patterns. The metric envelope approach provides better insights into the level of protection path diversity and message replication provide against different challenges, and enables more informed choices in opportunistic forwarding when network resilience becomes important.

  • 7.
    Boeira, Felipe
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Asplund, Mikael
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Barcellos, Marinho
    Univ Fed Rio Grande do Sul, Brazil.
    Decentralized proof of location in vehicular Ad Hoc networks2019Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 147, s. 98-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Future cooperative transportation systems will be highly dependent on correct situation awareness that can be established with the help of inter-vehicular communication. Location information from surrounding vehicles will most likely be used in such systems to make automated driving decisions, making it essential to guarantee location assurance. In this paper we propose Vouch+, which provides a scheme to improve trustworthiness of shared location information. The proposed scheme uses cryptographic primitives and mobility awareness to enable location proofs that work also in high-speed scenarios. Vouch+ takes a decentralized approach to establish trust in location information, but can also be used with future 5G infrastructure. The evaluation of Vouch+ using a synthetic dataset from the city of Cologne shows that using a decentralized approach is viable for cases where traffic is dense enough. In addition, simulation-based experiments show that Vouch+ is able to handle the high-mobility environment of vehicular networks and can counteract studied position-based attacks using reaction strategies.

  • 8.
    Borges Vieira, Alex
    et al.
    Universidade Federal de Juiz de Fora.
    De Carvalho Gomes, Pedro
    Computer Science Department, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
    Nacif, Jose
    Universidade Federal de Viçosa.
    Rodrigo, Mantini
    Universidade Federal de Minas Gerais.
    Almeida, Jussara M.
    Universidade Federal de Minas Gerais.
    Campos, Sérgio
    Universidade Federal de Minas Gerais.
    Characterizing SopCast Client Behavior2012Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 35, nr 8, s. 1004-1016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Live streaming media applications are becoming more popular each day. Indeed, some important TV channels already broadcast their live content on the Internet. In such scenario, Peer-to-Peer (P2P) applications are very attractive as platforms to distribute live content to large client populations at low costs. A thorough understanding of how clients of such applications typically behave, particularly in terms of dynamic patterns, can provide useful insights into the design of more cost-effective and robust solutions. With the goal of extending the current knowledge of how clients of live streaming applications typically behave, this paper provides a detailed characterization of clients of SopCast, a currently very popular P2P live streaming application. We have analyzed a series of SopCast transmissions collected using PlanetLab. These transmissions are categorized into two different types, namely, major event live transmissions and regular (or non-event) live transmissions. Our main contributions are: (a) a detailed model of client behavior in P2P live streaming applications, (b) the characterization of all model components for two different types of transmissions in the SopCast application, (c) the identification of qualitative and quantitative similarities and differences in the typical client behavior across different transmissions, and (d) the determination of parameter values for the proposed client behavior model to support the design of realistic synthetic workload generators.

  • 9.
    Budzisz, Lukasz
    et al.
    Department of Signal Theory and Communications (TSC), Universitat Politecnica de Catalunya.
    Ferrús, Ramon
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Grinnemo, Karl-Johan
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Fracchia, Roberta
    Motorola Labs – Paris, France.
    Galante, Giulio
    Istituto Superiore Mario Boella.
    Casadewall, Ferran
    Department of Signal Theory and Communications (TSC), Universitat Politecnica de Catalunya.
    Towards transport-layer mobility: Evolution of SCTP multihoming2008Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 31, nr 5, s. 980-998Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recently, growing availability of emerging wireless technologies has pushed the demand to integrate different wireless-network technologies such as: wireless local-area networks, cellular networks, and personal and short-range networks. The inter-working of heterogeneous radio access networks poses many technical challenges, with mobility management being one of the most important. In this paper we survey the existing proposals and show that transport-layer mobility is a viable candidate for implementing seamless handover in heterogeneous wireless access networks. Since the mobile Stream Control Transmission Protocol (mSCTP) is at the core of most relevant transport-layer mobility schemes being currently studied, we identify the key scenarios where the protocol can effectively leverage the multihoming feature to enhance handover support. Moreover, to provide the reader with a complete overview of the mSCTP's application area, we also survey the situations where the use of mSCTP-based schemes is not possible or has some limitations. Then, in one of the identified key scenarios, we investigate several challenging open issues related to path management and path-transition optimization by considering bandwidth-estimation schemes and link-layer support. Finally, we consider introducing concurrent multipath transfer (CMT) into mSCTP-based mobility schemes, as a future research direction.

  • 10.
    Chatzimisios, Periklis
    et al.
    Alexander Technological Educational Institute of Thessaloniki.
    Habib, Ibrahim
    University of New York.
    Bellavista, Paolo
    University of Bologna.
    Vinel, Alexey
    Saint-Petersburg Institute for Informatics and Automation, Russian Academy of Sciences.
    Guest editorial for the special issue on "Next generation networks service management"2011Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 34, nr 9, s. 1043-1044Artikel i tidskrift (Refereegranskat)
  • 11.
    Chiesa, Marco
    et al.
    Roma Tre University, Italy.
    Lospoto, G.
    Rimondini, M.
    Di Battista, G.
    Intra-domain routing with pathlets2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 46, s. 76-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Internal routing inside the network of an Internet Service Provider (ISP) affects the performance of lots of services that the ISP offers to its customers and is therefore critical to adhere to Service Level Agreements (SLAs), achieve a top-quality offer, and earn revenue. Existing technologies (most notably, MPLS) offer limited (e.g., with RSVP-TE), tricky (e.g., with OSPF metrics), or no control on internal routing paths. Recent research results address these shortcomings, but miss a few elements that would enable their application in an ISP's network. We introduce a new control plane, based on pathlet routing (Godfrey et al., 2009) [2], designed to operate in the network of an ISP and offering several nice features: it enables steering of network paths at different levels of granularity; it is scalable and robust; it supports independent configuration of specific network regions and differentiation of Quality of Service (QoS) levels; it can nicely coexist with other control planes and is independent of the data plane used in the ISP's network. Besides formally introducing the messages and algorithms of our control plane, we propose an experimental scalability assessment and comparison with OSPF, conducted in the simulation framework OMNeT++.

  • 12. Dannewitz, Christian
    et al.
    Kutscher, Dirk
    Ohlman, Börje
    Farrell, Stephen
    Ahlgren, Bengt
    RISE., Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Karl, Holger
    Network of Information (NetInf) - An Information-Centric Networking Architecture2013Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 36, s. 721-735Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Information-centric networking (ICN) is a promising approach to networking that has the potential to provide better -- more natural and more efficient -- solutions for many of today's important communication applications including but not limited to large-scale content distribution. This article describes the NetInf architecture -- a specific ICN approach that targets global-scale communication and supports many different types of networks and deployments, including traditional Internet access/core network configurations, data centers, as well as challenged and infrastructure-less networks. NetInf's approach to connecting different technology and administrative domains into a single information-centric network is based on a hybrid name-based routing and name resolution scheme. In this article, we describe the most important requirements that motivated the NetInf design. We present an architecture overview and discuss the different architecture elements such as naming, message forwarding, caching, and a NRS in detail. As efficient caching and a scalable NRS are two main success factors, we present an evaluation of both elements based on a theoretical analysis, complemental simulation results, and prototyping results. The results suggest that a scalable NRS for 10^15 and more objects with resolution latencies (well) below 100ms is possible, implying that a global NetInf that removes the need for today's application-specific overlay solutions is feasible.

  • 13.
    Dely, Peter
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Kassler, Andreas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Chow, Lawrence
    Stanford Univ, Stanford, CA 94305 USA..
    Bambos, Nicholas
    Stanford Univ, Stanford, CA 94305 USA..
    Bayer, Nico
    Telekom Innovat Labs, D-10587 Berlin, Germany..
    Einsiedler, Hans
    Telekom Innovat Labs, D-10587 Berlin, Germany..
    Peylo, Christoph
    Telekom Innovat Labs, D-10587 Berlin, Germany..
    BEST-AP: Non-intrusive estimation of available bandwidth and its application for dynamic access point selection2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 39, s. 78-91Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The coverage area of Access Points CAPS) in Wireless Local Area Networks (WLANs) often overlaps considerably. Hence, a station can potentially associate with many APs. In traditional IEEE 802.11 systems, the station associates to the AP with the strongest signal. This strategy may result in load imbalance between APs and thus low overall network throughput. This paper proposes a new mechanism for selecting the "best" AP based on a novel available bandwidth estimation scheme. The available bandwidth provided by an AP depends mainly on the signal quality and the load on the wireless channel. Based on measurements we first analyze how those factors vary stochastically over time and motivate why a frequent estimation of available bandwidth is necessary. We then develop BEST-AP, a system for Bandwidth ESTimation of Access Points, which uses regular data traffic to estimate the available bandwidth from all APs in reach in a non-intrusive way, even if they are on a different channel. Based on OpenFlow, BEST-AP allows the station to be associated with multiple APs simultaneously and to switch between APs with low overhead. Using the available bandwidth estimates, the system exploits the "best" AP for longer duration while probing the less good APs for shorter durations to update the bandwidth estimations. The evaluation in a WLAN testbed shows that with background load created from real WLAN traces, the dynamic selection of APs improves the throughput of a station by around 81%, compared to a static selection. When the station is mobile, the throughput increases by 176% on average.

  • 14.
    Di Marco, Piergiuseppe
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. Ericsson Research, Sweden.
    Athanasiou, Georgios
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. Institute of Communications and Computer Systems, National Technical University of Athens, Greece.
    Mekikis, Prodromos
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. Signal Theory and Communications Dept., Technical University of Catalonia, Barcelona, Spain.
    Fischione, Carlo
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    MAC-aware routing metrics for the internet of things2015Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of the internet of things (IoT) has significantly affected the concept of wireless networking. As the number of wireless devices is rising, new medium access control (MAC) and routing protocols have been developed to guarantee end-to-end network performance. When existing layered solutions are stacked together, there might be detrimental effects on the overall network performance. In this paper, an analysis of MAC and routing protocols for IoT is provided with focus on the IEEE 802.15.4 MAC and the IETF RPL standards. It is shown that existing routing metrics do not account for the complex interactions between MAC and routing, and thus novel metrics are proposed. This enables a protocol selection mechanism for selecting the routing option and adapting the MAC parameters, given specific performance constraints. Extensive analytical and experimental results show that the behavior of the MAC protocol can hurt the performance of the routing protocol and vice versa, unless these two are carefully optimized together by the proposed method.

  • 15. Domingo-Pascual, Jordi
    et al.
    Karlsson, Gunnar
    KTH.
    QofIS 20042006Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 29, nr 7, s. 799-800Artikel i tidskrift (Övrigt vetenskapligt)
  • 16.
    Ehlert, Sven
    et al.
    Fraunhofer Institute FOKUS.
    Zhang, Ge
    Fraunhofer Institute FOKUS.
    Geneiatakis, Dimitris
    University of the Aegean, Greece.
    Kambourakis, Georgios
    University of the Aegean, Greece.
    Dagiuklas, Tasos
    TEI of Mesolonghi, Greece.
    Markl, Jiri
    Nextsoft, Prague, Czech Republic.
    Sisalem, Dorgham
    Tekelec, Berlin, Germany.
    Two Layer Denial of Service Prevention on SIP VoIP Infrastructures2008Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 31, nr 10, s. 2443-2456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The emergence of Voice over IP (VoIP) has offered numerous advantages for end users and providers alike, but simultaneously has introduced security threats, vulnerabilities and attacks not previously encountered in networks with a closed architecture like the Public Switch Telephone Network (PSTN). In this paper we propose a two layer architecture to prevent Denial of Service attacks on VoIP systems based on the Session Initiation Protocol (SIP). The architecture is designed to handle different types of attacks, including request flooding, malformed message sending, and attacks on the underlying DNS system. The effectiveness of the prevention mechanisms have been tested both in the laboratory and on a real live VoIP provider network

  • 17.
    Eklund, Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT.
    Grinnemo, Karl-Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Using multiple paths in SCTP to reduce latency for signaling traffic2018Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 129, s. 184-196Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increase in traffic volumes as well as the heterogeneity in network infrastructure in the upcoming 5G cellular networks will lead to a dramatic increase in volumes of control traffic, i.e., signaling traffic, in the networks. Moreover, the increasing number of low-power devices with an on-off behavior to save energy will generate extra control traffic. These increased traffic volumes for signaling traffic, often generated as bursts of messages, will challenge the signaling application timing requirements on transmission. One of the major transport protocols deployed for signaling traffic in cellular networks is the Stream Control Transmission Protocol (SCTP), with support for multiple paths as well as for independent data flows. This paper evaluates transmission over several paths in SCTP to keep the latency low despite increasing traffic volumes. We explore different transmission strategies and find that concurrent multipath transfer over several paths will significantly reduce latency for transmission over network paths with the same or similar delay. Still, over heterogeneous paths, careful, continuous sender scheduling is crucial to keep latency low. To this end, we design and evaluate a sender scheduler that considers path characteristics as well as queuing status and data flows of different priority to make scheduling decisions. Our results indicate that by careful dynamic sender scheduling, concurrent multipath transfer could lead to reduced latency for signaling traffic irrespective of path or traffic characteristics.

  • 18. Erman, David
    et al.
    Ilie, Dragos
    Popescu, Adrian
    Measuring and Modeling the BitTorrent Content Distribution System2010Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 33, nr Sp. Iss. SI Suppl. 1, s. S22-S29Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The paper reports on a detailed study of the BitTorrent content distribution system. We first present a measurement infrastructure designed to allow detailed, message-level capture and analysis of P2P traffic. An associated modeling methodology is presented as well. These tools have been used to measure and model the BitTorrent protocol, which is observed to exhibit exponential characteristics of session interarrival times. We also observe that session durations and sizes are modeled with a lognormal distribution.

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  • 19.
    Fotouhi, Hossein
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portuga.
    Moreira, Daniel
    Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portugal.;Truphone, Lisbon, Portugal..
    Alves, Mario
    Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portugal..
    Yomsi, Patrick Meumeu
    Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portugal..
    mRPL plus: A mobility management framework in RPL/6LoWPAN2017Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 104, s. 34-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The next generation Internet (also known as Internet-of-Things - IoT), will ubiquitously integrate trillions of computing devices of all kinds, shapes and sizes. For this ubiquity to materialize, a key aspect will certainly be interoperability, the capability of different technologies (e.g. different communication protocols at both horizontal and vertical levels, different hardware platforms, different operating systems, fixed and mobile nodes, etc) to talk to and understand each other. A major enabler for this interoperability is the use of standard and commercial-off-the-shelf technologies (e.g. communication protocols, hardware platforms, operating systems). As IPv6 has become the de-facto communication technology for the Internet, 6LoWPAN has recently started paving the way for extending the Internet to low-power low-cost wireless devices. However, while mobility support will be a requirement (or at least beneficial) in many applications contexts, the support of mobile nodes in the default 6loWPAN/RPL protocol leads to excessive packet loss and delays. In this work, we show that interoperability between fixed and mobile nodes can be successfully achieved through the use of appropriate hand-off and topology management techniques. We propose a mobility management framework (dubbed mRPL+) unifying two hand-off models: (1) hard hand-off, where a mobile node has to break a link before finding a new link, and (2) soft hand-off, where a mobile node selects the new link before disconnecting from the current one. Importantly, mRPL+ is integrated in the 6LoWPAN/RPL stack in a backward compatible manner. Simulation results indicate that in a network with mobile nodes, packet delivery ratio with mRPL+ is nearly 100%, where RPL achieves 80% in best case. Hand-off process has a disconnected period of few milliseconds (hand-off delay = 4 ms), while RPL experiences few seconds of disconnection during node's mobility (3 - 10 s). (C) 2017 Elsevier B.V. All rights reserved.

  • 20.
    Gavrilovska, Liljana M.
    et al.
    Ss. Cyril and Methodius University, Skopje.
    Beek, Jaap van de
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Xie, Yong
    Huawei Technologies, Chengdu.
    Lidström, Erik
    Huawei Technologies, Stockholm.
    Riihijärvi, Janne
    RWTH Aachen University.
    Mähönen, Petri H.
    RWTH Aachen University.
    Atanasovski, Vladimir M.
    Ss. Cyril and Methodius University, Skopje, Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Denkovski, Daniel
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Rakovic, Valentin
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Enabling LTE in TVWS with radio environment maps: from an architecture design towards a system level prototype2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 53, s. 62-72Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports recent prototyping efforts that show the feasibility of the radio environmental map to enable efficient exploitation of TV white spaces by a cellular LTE system. We describe a flexible REM backend implementation, fully integrated with standard-compliant operational LTE base station equipment. Simulations results indicate that REMs enhance white-space detection by their means to incorporate accurate and local channel propagation information, while experimental laboratory results illustrate the feasibility and performance of transmitter localization capabilities in a REM.

  • 21.
    Grasic, Samo
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Arbetsvetenskap.
    Lindgren, Anders
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Revisiting a remote village scenario and its DTN routing objective2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 48, s. 133-140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Use of opportunistic connectivity together with the Delay Tolerant Network (DTN) architecture provides an economically viable alternative to traditional ICT solutions for communication challenged areas. Here, the remote village scenario is commonly established as a motive in terrestrial DTN research. However, the majority of the DTN research does not discuss the remote village scenario as a concept at any length. Instead, urban scenarios are employed, both as benchmarks and as target scenarios. This can be a problem as it does not take into account the specific characteristics of a concrete real-world remote village scenario. In this paper we discuss how these characteristics affect and shape the deployment of network and the network itself. Furthermore, we show how these network conditions forced us to change the focus from the traditional DTN routing objective forwarding problem to the traffic queuing problem. Finally, we discuss how the characteristics seen in the case study of one remote village can be generalized for other remote village scenarios. All material and observations used in this paper are drawn from our five years experiences of DTN deployments in remote mountainous villages of Sweden.

  • 22.
    Gross, James
    et al.
    Telecommunication Networks Group, Technical University of Berlin.
    Klaue, Jirka
    TU Berlin.
    Karl, Holger
    Universitaet Paderborn.
    Wolisz, Adam
    TU Berlin.
    Cross-Layer Optimization of OFDM Transmission Systems for MPEG-4 Video Streaming2004Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 27, nr 11, s. 1044-1055Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we study the performance of a combined link- and physical-layer approach for the downlink of a dynamic OFDM-frequency division multiple access transmission system delivering MPEG-4 video streams. The approach consists of three different mechanisms-queue management, resource allocation, and subcarrier assignment-which can be used separately as well as in combination. This crosslayer approach allows to utilize channel-related knowledge and semantic information of the streams packets. Consecutively adding these mechanisms to the studied system, we judge their respective impact on system performance. To do so, we present a new metric for quality assessment of long video transmissions (considerably longer than 10 s) and apply it to the simulation results. In particular, we introduce a local distortion threshold-based metric instead of an overall average judgment. We find that our combined system approach increases the number of supportable terminals per cell by up to 300%.

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  • 23.
    Gross, James
    et al.
    UMIC Research Centre, RWTH Aachen University, Germany.
    Reyer, Michael
    Institute for Theoretical Information Technology, RWTH Aachen University, Germany.
    Performance Prediction for OFDMA Systems with Dynamic Power and Subcarrier Allocation2011Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 34, nr 8, s. 973-984Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is well known that channel-dependent OFDMA resource assignment algorithms provide a significant performance improvement compared to static (i.e., channel-unaware) approaches. Such dynamic algorithms constantly adapt resource assignments to current channel states according to some objective function. Due to these dynamics, it is difficult to predict the resulting performance for such schemes given a certain scenario (characterized by the number of terminals in the cell and their average channel gains). In this paper we provide a novel, analytical framework for performance prediction, which takes dynamic power and subcarrier allocation into account. The analysis is based on fundamental transformations of the channel gains caused by the dynamic subcarrier allocations. This insight allows for deriving probability functions of the achieved rate per subcarrier which ultimately yields expressions for the expected minimal rates as well as outage probabilities for certain rate demands. Hence, the methods presented in this paper for performance prediction can be employed for admission control in systems with dynamic resource allocation. We illustrate the applicability of our derivations with respect to the capacity of 802.16e systems for Voice-over-IP and video streams. The results demonstrate a significant improvement compared to state-of-the art approaches but also reveal room for improvement of this approach compared to the optimal system performance.

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  • 24.
    Gupta, Lay
    et al.
    Washington University, USA.
    Jain, Raj
    Washington University, USA.
    Erbad, Aiman
    Qatar University, Qatar.
    Bhamare, Deval
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    The P-ART framework for placement of virtual network services in a multi-cloud environment2019Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 139, s. 103-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carriers' network services are distributed, dynamic, and investment intensive. Deploying them as virtual network services (VNS) brings the promise of low-cost agile deployments, which reduce time to market new services. If these virtual services are hosted dynamically over multiple clouds, greater flexibility in optimizing performance and cost can be achieved. On the flip side, when orchestrated over multiple clouds, the stringent performance norms for carrier services become difficult to meet, necessitating novel and innovative placement strategies. In selecting the appropriate combination of clouds for placement, it is important to look ahead and visualize the environment that will exist at the time a virtual network service is actually activated. This serves multiple purposes - clouds can be selected to optimize the cost, the chosen performance parameters can be kept within the defined limits, and the speed of placement can be increased. In this paper, we propose the P-ART (Predictive-Adaptive Real Time) framework that relies on predictive-deductive features to achieve these objectives. With so much riding on predictions, we include in our framework a novel concept-drift compensation technique to make the predictions closer to reality by taking care of long-term traffic variations. At the same time, near real-time update of the prediction models takes care of sudden short-term variations. These predictions are then used by a new randomized placement heuristic that carries out a fast cloud selection using a least-cost latency-constrained policy. An empirical analysis carried out using datasets from a queuing-theoretic model and also through implementation on CloudLab, proves the effectiveness of the PART framework. The placement system works fast, placing thousands of functions in a sub-minute time frame with a high acceptance ratio, making it suitable for dynamic placement. We expect the framework to be an important step in making the deployment of carrier-grade VNS on multi-cloud systems, using network function virtualization (NFV), a reality.

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  • 25. Ho, P. -H
    et al.
    Li, M.
    Yu, H. -F
    Jiang, X.
    Dán, György
    KTH, Skolan för elektro- och systemteknik (EES), Nätverk och systemteknik.
    Special Section on Mobile Content Delivery Networks2017Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 99Artikel i tidskrift (Refereegranskat)
  • 26.
    Hurtig, Per
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Enhancing SCTP Loss Recovery: An Experimental Evaluation of Early Retransmit2008Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 31, nr 16, s. 3778-3788Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To reduce cost and provide more flexible services, telecommunication operators are currently replacing traditional circuit-switched telephony networks with packet-switched IP networks. To support the stringent requirements of telephony signaling (SS7), the SIGTRAN working group of the IETF specified the transport protocol SCTP. SCTP was developed to overcome a number of problems that follow from using TCP for signaling transport. However, the design of SCTP was to a great extent still based on TCP, and some problems related to signaling transport were inherited. For example, the loss recovery mechanisms in SCTP are almost identical to those of TCP. This is a problem as signaling traffic has stringent requirements on timely message delivery. TCP was not designed to meet stringent requirements on timely message delivery, and therefore the loss recovery was not optimized for it. To optimize SCTP’s loss recovery for signaling traffic, we consider the loss recovery enhancement early retransmit. To make early retransmit even better suited for signaling traffic we propose a packet-based version, which was also recently included in the early retransmit specification. By experimentally evaluating this algorithm, we show that the packet-based early retransmit algorithm, in some cases, can reduce SCTP’s loss recovery time by 62%.

  • 27.
    Karlsson, Gunnar
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    Stiller, Burkhard
    Guest Editorial: Special Issue: QoFIS 20032005Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 28, nr 3, s. 257-258Artikel i tidskrift (Refereegranskat)
  • 28.
    Kouyoumdjieva, Sylvia T.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Karlsson, Gunnar
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Energy-Aware Opportunistic Mobile Data Offloading Under Full and Limited Cooperation2016Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 84, s. 84-95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Opportunistic networking (a.k.a. device-to-device communication) is considered a feasible means for offloading mobile data traffic. Since mobile nodes are battery-powered, opportunistic networks must be expected to satisfy the user demand without greatly affecting battery lifetime. To address this requirement, this work introduces progressive selfishness, an adaptive and scalable energy-aware algorithm for opportunistic networks used in the context of mobile data offloading. The paper evaluates the performance of progressive selfishness in terms of both application throughput and energy consumption via extensive trace-driven simulations of realistic pedestrian behavior. The evaluation considers two modes of nodal cooperation: full and limited, with respect to the percentage of nodes in the system that adopt progressive selfishness. The paper demonstrates that under full cooperation the proposed algorithm is robust against the distributions of node density and initial content availability. The results show that in certain scenarios progressive selfishness achieves up to 85% energy savings during opportunistic downloads while sacrificing less than 1% in application throughput. Furthermore, the study demonstrates that in terms of total energy consumption (by both cellular and opportunistic downloads) in dense environments the performance of progressive selfishness is comparable to downloading contents directly from a mobile network. Finally, the paper shows that progressive selfishness is robust against the presence of non-cooperative nodes in the system, and that in certain scenarios the system-level performance does not deteriorate significantly under limited cooperation even when 50% of the nodes in the system do not adhere to the specifics of the algorithm.

  • 29.
    Leblet, Jimmy
    et al.
    Telecom Bretagne.
    Li, Zhe
    Telecom Bretagne.
    Simon, Gwendal
    Telecom Bretagne.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Optimal network locality in distributed virtualized data-centers2011Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 34, nr 16, s. 1968-1979Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cost efficiency is a key aspect in deploying distributed service in networks within decentralized service delivery architectures. In this paper, we address this aspect from an optimization and algorithmic standpoint. The research deals with the placement of service components to network sites, where the performance metric is the cost for acquiring components between the sites. The resulting optimization problem, which we refer to as the k-Component Multi-site Placement Problem, is applicable to service distribution in a wide range of communication networking scenarios. We provide a theoretical analysis of the problems computational complexity, and develop an integer programming model for providing reference results for performance benchmarking. On the algorithmic side, we present four approaches: an algorithm with approximation guarantee and three heuristics algorithms. The first heuristic is derived from graph theory on domatic partition. The second heuristic, built on intuition, admits distributed computation. The third heuristic emphasizes on fairness in cost distribution among the sites. We report simulation results for sets of networks where cost is represented by round-trip time (RTT) originating from real measurements. For small networks, the integer model is used to study algorithm performance in terms of optimality. Large networks are used to compare the algorithms relatively to each other. Among the algorithms, the heuristic based on intuition has close-to-optimal performance, and the fairness heuristic achieves a good balance between single-site cost and the overall one. In addition, the experiments demonstrate the significance of optimization for cost reduction in comparison to a the random allocation strategy.

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  • 30. Man, Yemao
    et al.
    Ngai, Edith C.-H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Energy-efficient automatic location-triggered applications on smartphones2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 50, s. 29-40Artikel i tidskrift (Refereegranskat)
  • 31.
    Mancuso, Vincenzo
    et al.
    IMDEA Networks Institute, Spain.
    Peón Quirós, Miguel
    IMDEA Networks Institute, Spain; Ecole Polytech Fed Lausanne, Switzerland.
    Midoglu, Cise
    Simula Res Lab, Norway.
    Moulay, Mohamed
    IMDEA Networks Inst, Spain; University Carlos III of Madrid, Spain.
    Comite, Vincenzo
    IMDEA Networks Inst, Spain; University La Sapienza, Italy.
    Lutu, Andra
    Simula Res Lab, Norway.
    Alay, Ozgu
    Simula Res Lab, Norway.
    Alfredsson, Stefan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Rajiullah, Mohammad
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Mellia, Marco
    Politecnico di Torino, Italy.
    Khatouni, Ali Safari
    Politecnico di Torino, Italy.
    Hirsch, Thomas
    Celerway, Norway.
    Results from running an experiment as a service platform for mobile broadband networks in Europe2019Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 33, s. 89-101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article we present a selection from a vast range of experiments run with MONROE, our open experiment as a service (EaaS) platform for measurements and experimentation in Mobile Broadband Networks. We show that the platform can be used to benchmark network performance in a repeatable and controlled manner thanks to the collection of a rich set of geotagged metadata and the execution of discretionary user experiments. Indeed, with the sheer amount of data collected from 12 commercial mobile operators across Europe, MONROE offers an unprecedented opportunity to monitor, analyze and ultimately improve the status of current and future mobile broadband networks. Besides, we show how flexibly the platform allows combining metadata and experimental data series during the experiments or by means of post-processing, and show results produced by our own experiments as well as comment on results obtained by external research groups and developers that have been granted access to our platform.

  • 32.
    Modarres Razavi, Sara
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Mitigating signaling congestion in LTE location management by overlapping tracking area lists2012Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 35, nr 18, s. 2227-2235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Avoiding signaling congestion is a key aspect in location management of cellular networks. The signaling load in this context corresponds to the use of location update and paging messages for tacking user equipments (UEs). Signaling congestion may occur due to many UEs behaving in a similar manner, e.g., massive and simultaneous UE mobility in a train movement scenario. For Long Term Evolution (LTE) networks, location management can be based on the use of tracking area lists (TALs), each being a list containing multiple tracking areas (TAs). In this paper, the scheme of using TALs with overlapping TAs is applied for signaling congestion mitigation. One or multiple TALs that potentially overlap are allocated to each cell, and the TALs are assigned to the UEs that make their location updates in the cell. We derive linear programming formulations for finding the optimal proportional use of overlapping TALs for congestion avoidance. The main advantage of our approach is that it does not require the collection of detailed UE mobility information apart from what is available to the network. We report numerical results for realistic scenarios. The optimization approach yields promising results for reducing signaling congestion, and the performance region of optimized overlapping TALs goes significantly beyond the capability of the conventional TA scheme.

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  • 33.
    Nikolaevskiy, Ilya
    et al.
    Aalto University, Finland.
    Lukyanenko, Andrey
    Aalto University, Finland.
    Polishchuk, Tatiana
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Polishchuk, Valentin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Gurtov, Andrei
    Aalto University, Finland; Helsinki Institute Informat Technology, Finland; ITMO University, Russia.
    isBF: Scalable in-packet bloom filter based multicast2015Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 70, s. 79-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bloom filter (BF) based forwarding was proposed recently in several protocol alternatives to IP multicast. Some of these protocols avoid the state in intermediate routers and leave the burden of scalability management to the multicast source and end-hosts. Still, the existing BF-based protocols have scalability limitations and require explicit network management as well as non-trivial functionality from the network components. In this work we address the scalability limitations of the BF-based forwarding protocols by partitioning endhosts into clusters. We propose several algorithms to do the partitioning so as to decrease the overall traffic in the network. We evaluate our algorithms in a real Internet topology, demonstrating the ability of the proposed design to save up to 70% of traffic volume in the large-scale topology for big groups of subscribers, and up to 30% for small groups. (C) 2015 Elsevier B.V. All rights reserved.

  • 34. Nordström, Erik
    et al.
    Rohner, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Gunningberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Haggle: Opportunistic mobile content sharing using search2014Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 48, s. 121-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present Haggle, a content-sharing system for mobile devices, allowing users to opportunistically share content without the support of infrastructure. Mobile devices share content and interests over direct WiFi or Bluetooth links, and may store-carry-forward content on behalf of others based on interests, bridging otherwise disconnected devices. Unlike traditional Internet-based content sharing systems, Haggle faces disconnections, unpredictable mobility, and time-limited contacts, which pose unique challenges to the system's design and implementation. While similar content-sharing systems typically value every content item the same, Haggle uses a ranked search to judiciously decide which content to exchange, and in which order. The search matches a device's locally stored content against the interests of other users that the device has collected, prioritizing relevant content when contacts are time limited and resources scarce. Thus, search enables dissemination of content in order of how strongly users desire it, offering delay and resource savings by exchanging the content that matters. An optional content delegation mechanism allows Haggle to altruistically disseminate a limited amount of items based on the interests of third-party nodes, increasing the benefit of the network as a whole, and protecting against networks that are partitioned along interests. Ranked searches, combined with delegation, allow Haggle to balance the short-term benefit of exchanging a content item between two nodes against the long-term benefit to the network as a whole. We evaluate Haggle through a real-world experiment with mobile phones, running a picture sharing application, complemented by trace-based emulations. Our results show that a content item whose interest group (the nodes that desire it) has strong interests is delivered with lower delay, and to a higher fraction of members, than an item with a similar sized group with weak interests. Compared to a relevance-agnostic system, Haggle can deliver the most relevant items in one third of the time and at a lower cost. 

  • 35.
    Pajevic, Ljubica
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Karlsson, Gunnar
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Modeling opportunistic communication with churn2016Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    In opportunistic networking, characterizing contact patterns between mobile users is essential for assessing feasibility and performance of opportunistic applications. There has been significant efforts in deriving this characterization, based on observations and trace analyses; however, most of the previously established results were obtained by studying contact opportunities at large spatial and temporal scales. Moreover, the user population is considered to be constant: no user can join or leave the system. Yet, there are many examples of scenarios which do not fully adhere to the previous assumption and cannot be accurately described at large scales. Urban environments, such as smaller city districts, are characterized by highly dynamic user populations. We believe that scenarios with varying population require further investigation. In this paper, we present a novel modeling approach to study operation of opportunistic applications in scenarios where the population size is subjected to frequent changes, that is, it exhibits churn. We examine two location-based content sharing schemes: a purely opportunistic case and an infrastructure-supported content sharing scheme, for which we provide stochastic models based on stochastic differential equations (SDEs). We validate our models in five scenarios: a city area, subway station, conference, campus, and a scenario with a synthetic mobility model and we show that the models provide good representations of the investigated scenarios. © 2016.

  • 36. Palme, Jacob
    et al.
    Karlgren, Jussi
    KTH, Skolan för datavetenskap och kommunikation (CSC), Teoretisk datalogi, TCS.
    Pargman, Daniel
    Issues when designing filters in messaging systems1996Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 19, nr 2, s. 95-101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing size of messaging communities increases the risk of information overload, especially when group communication tools like mailing lists or asynchronous conferencing systems (like Usenet News) are used. Future messaging systems will require more capable filters to aid users in the selection of what to read. The increasing use of networks by non-computer professionals requires filters that are easier to use and manage than most filtering software today. Filters might use evaluations of messages made by certain users as an aid to filtering these messages for other users.

  • 37. Palme, Jacob
    et al.
    Karlgren, Jussi
    RISE, Swedish ICT, SICS.
    Pargman, Daniel
    Issues when designing filters in messaging systems1996Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 19, s. 95-101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing size of messaging communities increases the risk of information overload, especially when group communication tools like mailing lists or asynchronous conferencing systems (like Usenet News) are used. Future messaging systems will require more capable filters to aid users in the selection of what to read. The increasing use of networks by non-computer professionals requires filters that are easier to use and manage than most filtering software today. Filters might use evaluations of messages made by certain users as an aid to filtering these messages for other users.

  • 38.
    Parnes, Peter
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Synnes, Kåre
    Schefström, Dick
    Luleå tekniska universitet.
    Lightweight application level multicast tunnelling using mTunnel1998Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 21, nr 15, s. 1295-1301Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a system, named mTunnel, for application level tunnelling of IP-multicast traffic in a lightweight manner, where the end-user is responsible for deciding which MBone-sessions and which IP-multicast groups to tunnel. mTunnel is primarily designed for easy deployment and easy-to-manage tunnelling. Information about currently tunnelled sessions and control of mTunnel is provided through a Web-interface. To save bandwidth, tunnelled streams can be transcoded on the media level and traffic sent through the tunnel can be compressed by grouping several packets together and using statistical compression. The overall bandwidth reduction achieved, without modifying the media itself, has been measured to be between 5% and 14%, depending on the traffic and media type.

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  • 39.
    Parrow, Joachim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Sjödin, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för datorteknik.
    Designing a Multiway Synchronisation Protocol1996Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 19, nr 14, s. 1151-1160Artikel i tidskrift (Refereegranskat)
  • 40.
    Ploumidis, Manolis
    et al.
    University of Crete, Greece; .
    Pappas, Nikolaos
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Siris, Vasilios A.
    Athens University of Econ and Business, Greece.
    Traganitis, Apostolos
    University of Crete, Greece; University of Crete, Greece.
    On the performance of network coding and forwarding schemes with different degrees of redundancy for wireless mesh networks2015Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 72, s. 49-62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work explores the throughput and delay that can be achieved by various forwarding schemes, employing multiple paths and different degrees of redundancy, focusing on linear network coding. The key contribution of the study is an analytical framework for modeling the throughput and delay forvarious schemes, considering wireless mesh networks where unicast traffic is forwarded and hop-by-hop retransmissions are employed for achieving reliability. The analytical framework is generalized for an arbitrary number of paths and hops per path. Another key contribution of the study is the evaluation and extension of the numerical results, drawn from the analysis, through system-level simulations. Our results show that, in scenarios with significant interference, the best throughput-delay tradeoff is achieved by single path forwarding. Moreover, when significant interference is present and network coding employs the larger packet generation size, it experiences higher delay than the other schemes. This is due to the inter-arrival times aggregating over all coded packets required to decode a packet generation. (C) 2015 Elsevier B.V. All rights reserved.

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  • 41. Pourvali, M.
    et al.
    Cavdar, Cicek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Shaban, K.
    Crichigno, J.
    Ghani, N.
    Post-failure repair for cloud-based infrastructure services after disasters2017Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 111, s. 29-40Artikel i tidskrift (Refereegranskat)
  • 42.
    Sivieri, A.
    et al.
    Politecnico di Milano, Italy.
    Mottola, Luca
    RISE., Swedish ICT, SICS. Politecnico di Milano, Italy.
    Cugola, G.
    Politecnico di Milano, Italy.
    Building Internet of Things software with ELIoT2016Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 89-90, s. 141-153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present ELIoT, a development platform for Internet-connected smart devices. Unlike most solutions for the emerging "Internet of Things" (IoT), ELIoT allows programmers to implement functionality running within the networks of smart devices without necessarily leveraging the external Internet, and yet enables the integration of such functionality with Internet-wide services. ELIoT thus reconciles the demand for efficient localized performance, e.g., reduced latency for implementing control loops, with the need to integrate with the larger Internet. To this end, ELIoT's programming model provides IoT-specific inter-process communication facilities, while its virtual machine-based execution caters for the need of software reconfiguration and the devices' heterogeneity. Moreover, ELIoT addresses network-wide integration concerns by enabling standard-compliant interactions through REST and CoAP interfaces, with the added ability to dynamically reconfigure REST interfaces as application requirements evolve. We demonstrate the features and effectiveness of ELIoT based on a smart-home application, and quantitatively derive performance figures atop two hardware platforms compared to implementations using plain C or Java using the AllJoin framework. Compared to the C implementation, our results indicate that the performance cost for the increased programming productivity brought by ELIoT is still viable; for example, memory consumption in ELIoT is comparable, whereas the processing overhead remains within practical limits. Compared to the Java implementation using AllJoin, ELIoT provides a similar level of abstraction in programming, with much better performance both in memory consumption and processing overhead.

  • 43. Tian, Min
    et al.
    Voigt, Thiemo
    RISE., Swedish ICT, SICS, Computer Systems Laboratory.
    Naumowicz, Tomasz
    Ritter, Hartmut
    Schiller, Jochen
    Performance Considerations for Mobile Web Services2004Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 27, nr 11, s. 1097-1105Artikel i tidskrift (Refereegranskat)
  • 44. Tian, Ye
    et al.
    Li, Xiong
    Sangaiah, Arun Kumar
    Ngai, Edith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Song, Zheng
    Zhang, Lanshan
    Wang, Wendong
    Privacy-preserving scheme in social participatory sensing based on Secure Multi-party Cooperation2018Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 119, s. 167-178Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Social participant sensing has been widely used to collect location related sensory data for various applications. In order to improve the Quality of Information (QoI) of the collected data with constrained budget, the application server needs to coordinate participants with different data collection capabilities and various incentive requirements. However, existing participant coordination methods either require participants to reveal their trajectories to the server which causes privacy leakage, or tradeoff the location accuracy of participants for privacy, thereby leading to lower QoI. In this paper, we propose a privacy-preserving scheme, which allows application server to provide quasi-optimal QoI for social sensing tasks without knowing participants’ trajectories and identity. More specifically, we first suggest a Secure Multi-party Cooperation (SMC) based approach to evaluate participant’s contribution in terms of QoI without disclosing each individual’s trajectory. Second, a fuzzy decision based approach which aims to finely balance data utility gain, incentive budget and inferable privacy protection ability is adopted to coordinate participant in an incremental way. Third, sensory data and incentive are encrypted and then transferred along with participant-chain in perturbed way to protect user privacy throughout the data uploading and incentive distribution procedure. Simulation results show that our proposed method can efficiently select appropriate participants to achieve better QoI than other methods, and can protect each participant’s privacy effectively.

  • 45.
    Tombaz, Sibel
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab). Ericsson Research, Sweden.
    Sung, Ki Won
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Han, Sang Wook
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Zander, Jens
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    An economic viability analysis on energy-saving solutions for wireless access networks2016Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 75, s. 50-61Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As the energy bill for mobile operators rises with the continuing traffic growth, energy efficiency problems attract an increasing attention in the telecommunication industry. However, the investment for the implementation of any energy-saving solution could be so costly that it may not achieve the total cost reduction. Therefore, the economic viability of the proposed solutions is of substantial importance for the operators in the process of investment decisions. In this paper, we present a methodology for assessing the economic viability of energy-saving solutions. We conduct two case studies using the proposed methodology, and analyze the cost-benefit tradeoff for: (i) hardware upgrade enabling dynamic sleep mode operation at the base stations (BSs), and (ii) energy efficient network deployment minimizing the network energy consumption. Simulation results show that the hardware upgrade can save up to 60% of energy consumption particularly when the high data rate requirement forces low network resource utilization. Consequently, the solution is shown to be increasingly cost effective as the unit energy cost increases. Network deployment optimized for energy efficiency is shown to bring about further energy savings, but it demands denser deployment of BSs. Thus, it is not deemed as economically viable considering today's cost values.

  • 46.
    Tsai, Ming-Fong
    et al.
    National Cheng Kung University, Taiwan.
    Chilamkurti, Naveen
    La Trobe University, Melbourne, Australia.
    Zeadally, Sherali
    University of the District of Columbia, Washington, DC 20008, United States.
    Vinel, Alexey
    Saint-Petersburg Institute for Informatics and Automation, Russian Academy of Sciences.
    Concurrent multipath transmission combining forward error correction and path interleaving for video streaming2011Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 34, nr 9, s. 1125-1136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Video streaming is a popular application on next generation networks (NGNs). However, video streaming over NGNs has many challenges due to the high bit error rates of these networks. Forward error correction (FEC) is often applied to improve the quality of video streaming. However, continuous lost packets decrease the recovery performance of FEC protection in NGNs. To disperse continuous lost packets to different FEC blocks, we propose a concurrent multipath transmission that combines FEC with path interleaving. Our proposed control scheme adaptively adjusts the FEC block length and concurrently sends data interleaved over multiple paths. Experimental results with our approach show improved packet loss and signal to noise ratio performance. © 2010 Elsevier B.V. All rights reserved.

  • 47.
    Turull, Daniel
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Sjödin, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Olsson, Robert
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Network Systems Laboratory (NS Lab).
    Pktgen: Measuring performance on high speed networks2016Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 82, s. 39-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract Pktgen is a tool for high-speed packet generation and testing. It runs in the Linux kernel, and is designed to accommodate a wide range of network performance tests. Pktgen consists of a packet generator, a receiver, and a protocol that defines the format for test packets. This paper describes the design of pktgen, and discusses its usage as a capable performance testing tool. The design is focused on performance, and in order to generate packets at high packet rate, pktgen takes advantage of multicore systems and multi-queue features on modern network cards. To support realistic heterogeneous traffic patterns, pktgen can generate multiple simultaneous UDP flows. Pktgen supports measurements of throughput, latency, packet inter-arrival time, and packet delay variation with a wide-range of fine-grained user specified rates. We evaluate and compare pktgen to other tools, and show that it is more than an order of magnitude faster than current Linux applications such as Iperf and Netperf, and has the same upper limit on performance as special-purpose high-speed tools, such as DPDK and Netmap, when it comes to throughput measurements with user-specified rate.

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  • 48.
    Xu, Changqiao
    et al.
    State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing.
    Quan, Wei
    National Engineering Laboratory for Next Generation Internet Technologies, School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing.
    Vasilakos, Athanasios
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zhang, Hongke
    National Engineering Laboratory for Next Generation Internet Technologies, School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing.
    Muntean, Gabriel-Miro
    School of Electronic Engineering, Network Innovations Centre, Rince Institute, Dublin City University.
    Information-centric cost-efficient optimization for multimedia content delivery in mobile vehicular networks2017Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 99, s. 93-106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Providing high-quality multimedia services is a challenging and high-cost task in mobile vehicular networks due to intermittent connectivity, highly dynamic capacity, mostly associated to heterogeneous hosts distribution and their high mobility. Information-centric networking (ICN), which adopts novel content-based dissemination instead of the traditional host-based one, has great potential to accomplish cost-efficient quality-oriented multimedia delivery. This paper proposes a novel cost-Efficient Multimedia content Delivery approach (EcoMD) in vehicular networks leveraging the ICN features. In EcoMD, two essential factors are first analyzed and modeled: content mobility and supply-demand balance, and then, a mixed integer programming (MIP) optimization is formulated to minimize the economic cost associated to guaranteed the quality level of multimedia services. To resolve this NP-hard problem, heuristic mechanisms are proposed covering three aspects: priority-based path selection, least-required source maintaining and on-demand caching enhancement. By comparison with existing state-of-the-art solutions, simulation results demonstrate how EcoMD provides an improved performance in terms of start-up delay, jitter, playback continuity, and Quality of Experience (QoE) while particularly reduces the economic cost.

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