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  • 151.
    Reis, Andre B
    et al.
    Institute of Telecommunications, University of Aveiro, Portugal.
    Chakareski, Jacob
    Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Sargento, Susana
    Institute of Telecommunications, University of Aveiro, Portugal.
    Distortion Optimized Multi-Service Scheduling for Next-Generation Wireless Mesh Networks2010In: : INFOCOM IEEE Conference on Computer Communications Workshops , 2010, IEEE Press, 2010Conference paper (Refereed)
    Abstract [en]

    Distributing multimedia content over wireless networks is challenging due to the limited resource availability and the unpredictability of wireless links. As more and more users demand wireless access to (real-time) multimedia services, the impact of constrained resources is different for different media types. Therefore, understanding this impact and developing mechanisms to optimize content delivery under resource constraints according to user perception will be key in improving user satisfaction. In this paper, we develop a novel scheduling algorithm for multi-hop wireless networks, which optimizes packet delivery for multiple audio, video and data flows according to user perceivable quality metrics. We formulate a multidimensional optimization problem to minimize the overall distortion while satisfying resource constraints for the wireless links. Our Quality-of-Experience (QoE)-optimized scheduler makes use of models to determine the user's perception of quality that are specific to the type of service being provided. Our experimental results, obtained with the NS-2 IEEE 802.16 MESH-mode simulator, show that distortion-aware scheduling can significantly increase the perceived quality of multimedia streaming under bandwidth constraints. As the scheduler allows the modeling of fairness constraints among multiple competing flows, we also demonstrate an improvement in fairness across different flows.

  • 152.
    Reis, Andre B.
    et al.
    Institute of Telecommunications, University of Aveiro, Portugal.
    Chakareski, Jacob
    EPFL, Switzerland;.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Sargento, Susana
    *Institute of Telecommunications, University of Aveiro, Portugal.
    Quality of Experience Optimized Scheduling in Multi-Service Wireless Mesh Networks2010In: Proceedings of International Conference on Image Processing (ICIP) 2010, IEEE conference proceedings, 2010, p. 3233-3236Conference paper (Refereed)
    Abstract [en]

    A growing trend has emerged in network architecture research to switch focus from Quality of Service (QoS) to Quality of Experience (QoE) optimization. In this paper, we first present QoE models that characterize user satisfaction of video, audio, and data services over wireless networks. We then develop a novel packet scheduling algorithm for multi-hop wireless networks that jointly optimizes the delivery of multiple video, audio, and data flows according to the QoE metrics. We formulate a multidimensional optimization problem that minimizes the overall distortion across all flows for the given network resources on wireless links. Fairness constraints over the flows are also considered as part of the optimization. Our experimental results, obtained with the NS-2 IEEE 802.16 MESH-mode simulator, show that distortion-aware scheduling can significantly increase the perceived quality of different wireless services under bandwidth constraints. Additionally, improved fairness across the competing flows is demonstrated relative to conventional scheduling techniques.

  • 153.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bozakov, Zdravko
    DELL EMC Research Europe, Ovens, Ireland.
    Mangiante, Simone
    DELL EMC Research Europe, Ovens, Ireland.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    A NEAT framework for application-awareness in SDN environments2017In: 2017 IFIP Networking Conference (IFIP Networking) and Workshops, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    Software-Defined Networking (SDN) has led to a paradigm shift in the way how networks are managed and operated. In SDN environments the data plane forwarding rules are managed by logically centralized controllers operating on global view of the network. Today, SDN controllers typically posses little insight about the requirements of the applications executed on the end-hosts. Consequently, they rely on heuristics to implement traffic engineering or QoS support. In this work, we propose a framework for application-awareness in SDN environments where the end-hosts provide a generic interface for the SDN controllers to interact with. As a result, SDN controllers may enhance the end-host’s view of the attached network and deploy policies into the edge of the network. Further, controllers may obtain information about the specific requirements of the deployed applications. Our demonstration extends the OpenDaylight SDN controller to enable it to interact with end-hosts running a novel networking stack called NEAT. We demonstrate a scenario in which the controller distributes policies and path information to manage bulk and low-latency flows. 

  • 154.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Curadoo, Marilia
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Multipathing In Software Defined Networking: Interaction between SDN and MPTCP2015In: Proceedings of SWE-CTW 2015, May 27th – 29th, Karlstad, Sweden., 2015Conference paper (Refereed)
  • 155.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ghazzai, Hakim
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Stevens Institute of Technology, USA.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Optimal Steerable mmWave Mesh Backhaul Reconfiguration2018In: 2018 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM), IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    Future 5G mobile networks will require increased backhaul (BH) capacity to connect a massive amount of high capacity small cells (SCs) to the network. Because having an optical connection to each SC might be infeasible, mmWave-based (e.g. 60 GHz) BH links are an interesting alternative due to their large available bandwidth. To cope with the increased path loss, mmWave links require directional antennas that should be able to direct their beams to different neighbors, to dynamically change the BH topology, in case new nodes are powered on/off or the traffic demand has changed. Such BH adaptation needs to be orchestrated to minimize the impact on existing traffic.This paper develops a Software-defined networking-based framework that guides the optimal reconfiguration of mesh BH networks composed by mmWave links, where antennas need to be mechanically aligned.By modelling the problem as a Mixed Integer Linear Program (MILP), its solution returns the optimal ordering of events necessary to transition between two BH network configurations. The model creates backup paths whenever it is possible, while minimizing the packet loss of ongoing flows. A numerical evaluation with different topologies and traffic demands shows that increasing the number of BH interfaces per SC from 2 to 4 can decrease the total loss by more than 50%. Moreover, when increasing the total reconfiguration time, additional backup paths can be created, consequently reducing the reconfiguration impact on existing traffic.

  • 156.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    A SDN Controller Architecture for Small Cell Wireless Backhaul using a LTE Control Channel2016In: Proceedings of the IEEE WoWMoM, IEEE, 2016Conference paper (Refereed)
  • 157.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Small Cell Wireless Backhaul Reconfiguration Using Software-Defined Networking2017In: Wireless Communications and Networking Conference (WCNC), 2017 IEEE, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    In order to increase the capacity of next generation mobile networks, network densification is a key aspect to provide better coverage and increased data rates to end users. Network operators are thinking to deploy wireless backhaul solutions to cut down cabling costs for connecting the small cell nodes. Consequently, the next generation mobile network architecture may contain a massive amount of small cells that are connected through wireless backhaul links, forming mesh or tree structures towards the core network, under the umbrella coverage of eNodeB type macro cells. In this paper, we use a Software-Defined Networking (SDN) based architecture for the operation and management of such small cell backhaul networks. By extending OpenFlow, the SDN controller is able to reconfigure not only the routing, but also the wireless backhaul configuration, such as channel assignment to backhaul links. We demonstrate the effectiveness of our approach by using testbed measurements and show that, when using our SDN-based reconfiguration, the network downtime for existing traffic due to channel re-assignment is significantly reduced, when comparing to a distributed routing based approach. Moreover, by using SDN based fast-failover techniques, we can instantaneously redirect traffic to other neighbors when links fail or neighbors are powered down, without the need for controller interaction.

  • 158.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Koslowski, Konstantin
    Fraunhofer Heinrich Hertz Institute, Germany.
    Daube, Julian
    Fraunhofer Heinrich Hertz Institute, Germany.
    Ghazzai, Hakim
    Stevens Institute of Technology, New Jersey.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Sakaguchi, Kei
    Tokyo Institute of Technology, Japan.
    Haustein, Thomas
    Fraunhofer Heinrich Hertz Institute, Germany.
    mmWave Backhaul Testbed Configurability Using Software-Defined Networking2019In: Wireless Communications & Mobile Computing, ISSN 1530-8669, E-ISSN 1530-8677, p. 1-24, article id 8342167Article in journal (Refereed)
    Abstract [en]

    Future mobile data traffic predictions expect a significant increase in user data traffic, requiring new forms of mobile network infrastructures. Fifth generation (5G) communication standards propose the densification of small cell access base stations (BSs) in order to provide multigigabit and low latency connectivity. This densification requires a high capacity backhaul network. Using optical links to connect all the small cells is economically not feasible for large scale radio access networks where multiple BSs are deployed. A wireless backhaul formed by a mesh of millimeter-wave (mmWave) links is an attractive mobile backhaul solution, as flexible wireless (multihop) paths can be formed to interconnect all the access BSs. Moreover, a wireless backhaul allows the dynamic reconfiguration of the backhaul topology to match varying traffic demands or adaptively power on/off small cells for green backhaul operation. However, conducting and precisely controlling reconfiguration experiments over real mmWave multihop networks is a challenging task. In this paper, we develop a Software-Defined Networking (SDN) based approach to enable such a dynamic backhaul reconfiguration and use real-world mmWave equipment to setup a SDN-enabled mmWave testbed to conduct various reconfiguration experiments. In our approach, the SDN control plane is not only responsible for configuring the forwarding plane but also for the link configuration, antenna alignment, and adaptive mesh node power on/off operations. We implement the SDN-based reconfiguration operations in a testbed with four nodes, each equipped with multiple mmWave interfaces that can be mechanically steered to connect to different neighbors. We evaluate the impact of various reconfiguration operations on existing user traffic using a set of extensive testbed measurements. Moreover, we measure the impact of the channel assignment on existing traffic, showing that a setup with an optimal channel assignment between the mesh links can result in a 44% throughput increase, when compared to a suboptimal configuration.

  • 159.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ogawa, Hiroaki
    Tokyo Institute of Technology.
    Khanh Tran, Gia
    Tokyo Institute of Technology.
    Sakaguchi, Kei
    Tokyo Institute of Technology.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Turning the knobs on OpenFlow-based resiliency in mmWave small cell meshed networks2017In: Globecom Workshops (GC Wkshps), 2017 IEEE: 5G Testbed, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    As a solution to cope with the increase of wireless network traffic for future 5G networks, the IEEE 802.11ad standard enables multi-gigabit connectivity within the 60 GHz spectrum. Since these networks typically have low range, a vast number of small cells is required to form a wireless backhaul that can be easily affected by temporary failures due to blockage/interference. Software-defined Networking (SDN) is a paradigm that allows the centralization of the control plane management, which can be applied to mmWave wireless backhaul networks. Using SDN enables the possibility of having resilience mechanisms in the network, such as Fast-Failover (FF) group tables in the OpenFlow (OF) protocol. In this paper, we analyse resilient forwarding configurations upon temporary link failures. We perform our evaluation on a 4 small cell testbed with multiple IEEE 802.11ad interfaces, showing how OF-based resiliency can be applied, through FF and the Bidirectional-Forwarding Detection (BFD) protocol. Our results show how BFD can be tuned to improve the link state monitoring, and how a local reactive failover mechanism can benefit ongoing traffic in small cell meshed backhaul networks.

  • 160.
    Schmidt, Holger
    et al.
    Institute of Distributed Systems Ulm University Germany .
    Aksoy, Burcin
    Institute of Distributed Systems Ulm University Germany.
    Hauck, Franz J.
    Institute of Distributed Systems Ulm University Germany.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    How well does JXTA fit Peer-to-Peer SIP?2008In: Proceedings of 2008 IEEE International Conference on Communications, IEEE Press, 2008, p. 1792-1796Conference paper (Refereed)
    Abstract [en]

    More and more people use voice over IP instead of traditional telephone networks. The Session Initiation Protocol (SIP), a protocol for session management in general, becomes the standard protocol in use. However, SIP relies on central servers and thus maintaining the infrastructure is costly. This results in the trend to transfer peer-to-peer concepts to SIP to overcome administration efforts due to self-organisation of the participants.In this paper, we propose a novel JXTA-based peer-to-peer architecture for SIP signalling. JXTA is a generic and open peer-to-peer platform, which provides basic infrastructure services for building peer-to-peer applications. Our concept does not need central entities for maintaining the SIP traffic, while maintaining compatibility with standard SIP. Additionally, we seamlessly added service location capabilities into our infrastructure to support service discovery in dynamic environments. We evaluated our concept in comparison to standard SIP within three scenarios: local area network, point-to-point network and wide area network. The results show that our approach fits well in terms of response time but results in more traffic for maintaining the peer-to-peer overlay.

  • 161. Schorr, Andreas
    et al.
    Hauck, Franz
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Description and Lookup of Media-Stream Adaptation Services2006Conference paper (Refereed)
    Abstract [en]

    In this paper, we propose a new application of RDF that enables the description of services offered by so-called media-stream adaptation nodes (MSANs). An MSAN can manipulate a stream by changing media format and quality on-the-fly during an ongoing streaming process. An accurate description of the offered services is necessary, because different clients may have very specific requirements that cannot be fulfilled by every MSAN. In this paper, we propose an RDF-based vocabulary that enables an MSAN to provide such an accurate description of its services. We also demonstrate how clients can formulate search queries to find a services provider that fulfills their specific requirements

  • 162.
    Shams Shafigh, Alireza
    et al.
    Department of computer science Islamic Azad University of Damavand Tehran, Iran.
    Abdollahi, Kamran
    Department of computer science Islamic Azad University of Damavand Tehran, Iran.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Improving Performance of On Demand Multicast Routing by using Fuzzy Logic2010In: Proceedings of IEEE International Conference on Wireless Communications, Networking and Information Security (WCNIS 2010), IEEE Press, 2010, p. 525-529Conference paper (Refereed)
    Abstract [en]

    A Mobile ad hoc network is a collection of wireless communication nodes that dynamically organize themselves to form a network without the need for any fixed infrastructure or centralized administration. Multicasting can be considered as an efficient way to deliver information from source nodes to several client nodes. Although multicast routing algorithms are desirable, their forwarding structure and network resource consumption makes them significantly less efficient than unicast routing algorithms. In this research, a fuzzy-based policy was used to improve performance of On-Demand Multicast Routing Protocol. The main goal of FBODMRP is to establish a small, high quality and efficient forwarding group. An evaluation shows that our approach increases packet delivery rate by up to 40%, reduces average end to end delay and consumed power by about 35% and 45% respectively.

  • 163. Szwabe, Andrzej
    et al.
    Schorr, Andreas
    Tyskland.
    Hauck, Franz J.
    Tyskland.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Dynamic Multimedia Stream Adaptation and Rate Control for Heterogeneous Networks2006In: Journal of Zhejiang University SCIENCE C, ISSN 1869-1951, E-ISSN 1869-196X, Vol. 7, no 1 Suppl., p. 63-69Article in journal (Refereed)
  • 164. Szwabe, Andrzej
    et al.
    Schorr, Andreas
    Hauck, Franz J.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Dynamic Multimedia Stream Adaptation and Rate Control for Heterogeneous Networks2006Conference paper (Refereed)
    Abstract [en]

    : Dynamic adaptation of multimedia content is seen as an important feature of next generation networks and pervasive systems to enable terminals and applications to adapt to changes in e.g. context, access network, and available QoS due to mobility of users, devices or sessions. We present the architecture of a multimedia stream adaptation service which enables communication between terminals having heterogeneous hard- and software capabilities and served by heterogeneous networks. The service runs on special content adaptation nodes which can be placed at any location within the network. The flexible structure of our architecture allows using a variety of different adaptation engines. A generic transcoding engine is used to change the codec of streams. An MPEG-21 DIA based transformation engine allows adjusting the data rate of scalable media streams. An intelligent decision-taking engine implements adaptive flow control which takes into account current network QoS parameters and congestion information. Measurements demonstrate the quality gains achieved through adaptive congestion control mechanisms under conditions typical for a heterogeneous network

  • 165.
    Taheri, Javid
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    vmBBThrPred: A Black-Box Throughput Predictor for Virtual Machines in Cloud Environments2016In: SERVICE-ORIENTED AND CLOUD COMPUTING, (ESOCC 2016) / [ed] M. Aiello, E.B.Johnsen, S. Dustdar, I. Georgievski, Cham: Springer, 2016, Vol. 9846, p. 18-33Conference paper (Refereed)
    Abstract [en]

    In today's ever computerized society, Cloud Data Centers are packed with numerous online services to promptly respond to users and provide services on demand. In such complex environments, guaranteeing throughput of Virtual Machines (VMs) is crucial to minimize performance degradation for all applications. vmBBThrPred, our novel approach in this work, is an application-oblivious approach to predict performance of virtualized applications based on only basic Hypervisor level metrics. vmBBThrPred is different from other approaches in the literature that usually either inject monitoring codes to VMs or use peripheral devices to directly report their actual throughput. vmBBThrPred, instead, uses sensitivity values of VMs to cloud resources (CPU, Mem, and Disk) to predict their throughput under various working scenarios (free or under contention); sensitivity values are calculated by vmBBProfiler that also uses only Hypervisor level metrics. We used a variety of resource intensive benchmarks to gauge efficiency of our approach in our VMware-vSphere based private cloud. Results proved accuracy of 95% (on average) for predicting throughput of 12 benchmarks over 1200 h of operation.

  • 166.
    Taheri, Javid
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zomaya, Albert Y.
    University of Sydney, Australia.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    vmBBProfiler: A BlackBox Profiling Approach to Quantify Sensitivity of Virtual Machines to Shared Cloud Resources2017In: Computing, ISSN 0010-485X, E-ISSN 1436-5057, Vol. 99, no 12, p. 1149-1177Article in journal (Refereed)
    Abstract [en]

    Virtualized Data Centers are packed with numerous web and cloud servicesnowadays. In such large infrastructures, providing reliable service platforms dependsheavily on efficient sharing of physical machines (PMs) by virtual machines (VMs).To achieve efficient consolidation, performance degradation of co-located VMs mustbe correctly understood, modeled, and predicted. This work is a major step towardunderstanding such baffling phenomena by not only identifying, but also quantifyingsensitivity of general purpose VMs to their demanded resources. vmBBProfiler, ourproposed system in this work, is able to systematically profile behavior of any generalpurpose VM and calculate its sensitivity to system provided resources such as CPU,Memory, and Disk. vmBBProfiler is evaluated using 12 well-known benchmarks,varying from pure CPU/Mem/Disk VMs to mixtures of them, on three different PMsin our VMware-vSphere based private cloud. Extensive empirical results conductedover 1200h of profiling prove the efficiency of our proposed models and solutions; italso opens doors for further research in this area. vmBBProfiler: a black-box profiling approach to quantify sensitivity of virtual machines to shared cloud resources (PDF Download Available).

  • 167. Tebbe, H.
    et al.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    QAMNet: Providing Quality of Service to Ad-hoc Multicast Enabled Networks2006Conference paper (Refereed)
    Abstract [en]

    Mobile Ad-hoc networking has been considered as one of the most important and essential technologies that support future Pervasive Computing Scenarios and 4G networks. In a mobile Ad-hoc Network (MANET), support for multicast communication is essential in order to minimize overhead for group communication. For group conferencing services, controlling the end-to-end delay is important to provide high quality communication. In this paper, we present QAMNet, an approach to improve the Quality of Service (QoS) for multicast communication in MANETs. We extend existing approaches of mesh based multicasting by introducing traffic prioritization, distributed resource probing and admission control mechanisms, adaptive rate control of non-real-time traffic based on Medium Access Control (MAC) layer feedback so as to maintain low delay and required throughput for real-time multicast flows. Simulation results show that our approach is as scalable as mesh based deliver structures and does not require significantly more states than normal mesh based multicasting protocols. As we reuse signaling packets of mesh based multicast packets, we do not introduce additional signaling overhead

  • 168. Tebbe, H.
    et al.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Quality of Service for Ad hoc Multicast Communication2005Conference paper (Refereed)
  • 169. Tebbe, Harald
    et al.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Ruiz, Pedro M.
    QoS-aware Mesh Construction to Enhance Multicast Routing in Mobile Ad Hoc Networks (Invited Paper)2006Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Mobile Ad-hoc Networks (MANETs) are seen as an essential technology to support future Pervasive Computing Scenarios and 4G networks. In a MANET, efficient support of multipoint communications is essential in order to provide services like group audio and video conferencing, dissemination of data to a set of receivers or collaboration of a group of users. However, most of these interactive services have very strong requirements regarding delay and bandwidth. Controlling the end-to-end delay and maintaining low packet loss rate is vital to support interactive multimedia applications in MANETs. In this paper, we present QAMNet, an approach to improve the Quality of Service (QoS) for multicast communication in MANETs. We extend existing mesh based multicast routing protocols by introducing traffic prioritization, distributed resource probing and admission control mechanisms and adaptive rate control of non-real-time traffic based on Medium Access Control (MAC) layer feedback to maintain low delay and required throughput for real-time multicast flows. Simulation results show that, by reusing control messages already used by those protocols, our approach does not significantly increase control overhead nor state stored at nodes compared while it manages to increase packet delivery ratio and reduce latency for real-time traffic

  • 170. Teck Meng, L.
    et al.
    Sung Lee, Bu
    Kiat Yeo, Chai
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Boon Chong, S.
    IPv6 Network Mobility on Ad Hoc Network for Public Transportation Systems2005Conference paper (Refereed)
  • 171.
    Tran, Gia Khanh
    et al.
    Tokyo Institute of Technology, Japan.
    Santos, Ricardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ogawa, Hiroaki
    Tokyo Institute of Technology, Japan.
    Nakamura, Makoto
    Tokyo Institute of Technology, Japan.
    Sakaguchi, Kei
    Tokyo Institute of Technology, Japan.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Context-based dynamic meshed backhaul construction for 5G heterogeneous networks2018In: Journal of Sensor and Actuator Networks, ISSN 2224-2708, Vol. 7, no 4, article id 43Article in journal (Refereed)
    Abstract [en]

    Five-G heterogeneous network overlaid by millimeter-wave (mmWave) access employs mmWave meshed backhauling as a promising cost-efficient backhaul architecture. Due to the nature of mobile traffic distribution in practice which is both time-variant and spatially non-uniform, dynamic construction of mmWave meshed backhaul is a prerequisite to support the varying traffic distribution. Focusing on such scenario of outdoor dynamic crowd (ODC), this paper proposes a novel method to control mmWave meshed backhaul for efficient operation of mmWave overlay 5G HetNet through Software-Defined Network (SDN) technology. Our algorithm is featured by two functionalities, i.e., backhauling route multiplexing for overloaded mmWave small cell base stations (SC-BSS) and mmWave SC-BSS' ON/OFF status switching for underloaded spot. In this paper, the effectiveness of the proposed meshed network is confirmed by both numerical analyses and experimental results. Simulations are conducted over a practical user distribution modeled from measured data in realistic environments. Numerical results show that the proposed algorithm can cope with the locally intensive traffic and reduce energy consumption. Furthermore, a WiGig (Wireless Gigabit Alliance certified) device based testbed is developed for Proof-of-Concept (PoC) and preliminary measurement results confirm the proposed dynamic formation of the meshed network's efficiency.

  • 172.
    Trung Luong, Tuan
    et al.
    School of Computer Engineering, Nanyang Technology University, Singapore.
    Sung Lee, Bu
    School of Computer Engineering, Nanyang Technology University, Singapore.
    Kiat Yeo, Chai
    School of Computer Engineering, Nanyang Technology University, Singapore.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Efficient Channel Assignment and Routing Protocol for Multiple Channels Multiple Interfaces Wireless Mesh Network2010In: Proceedings of the 2010 IFIP Wireless Days, IEEE Press, 2010Conference paper (Refereed)
    Abstract [en]

    Wireless technologies, such as 802.11a, provide multiple non-overlapping channels. Effective utilization of the multiple available channels helps to reduce the channel interference so that multiple simultaneous data transmissions can occur and thus increasing network capacity. Initial approach for exploiting multiple available channels is dedicating one interface for each channel. However, this approach incurs high hardware cost and is not practical. This paper presents a distributed channel assignment and routing protocol that can take advantage of multiple available channels with two interfaces by dynamically switching the channels for forwarding packets based on data traffic. Our model can work with any existing routing protocol, we extend the AODV routing protocol with suitable modification and an additional routing metric to present the proposed AODV-M algorithm. Simulation results show that the proposed algorithms exploit the available channels to significantly increase the network capacity while reducing the end-to-end delay time.

  • 173.
    Tsaoussidis, Vassilis
    et al.
    Democritus University of Thrace .
    Kassler, AndreasKarlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.Koucheryavy, YevgeniTampere University of Technology .Mellouk, AbdelhamidUniversity of Paris-Est Créteil VdM (UPEC) - LiSSi .
    Proceedings of the Wired/Wireless Internet Communication, 11th International Conference, WWIC 20132013Conference proceedings (editor) (Refereed)
  • 174.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Dely, Peter
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Bayer, Nico
    Telekom Innovation Laboratories.
    Einsiedler, Hans
    Telekom Innovation Laboratories.
    Peylo, Christoph
    Telekom Innovation Laboratories.
    CloudMAC: Towards Software Defined WLANs2012In: Mobicom '12 Proceedings of the 18th annual international conference on Mobile computing and networking, Association for Computing Machinery (ACM), 2012, p. 393-396Conference paper (Refereed)
  • 175.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Low frequency assist for mmWave backhaul - the case for SDN resiliency mechanisms2017In: Communications Workshops (ICC Workshops), 2017 IEEE International Conference on, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    In 5G, network densification is a major concern for operators. When a massive amount of small cells are deployed, the backhaul capacity is crucial and researchers are exploring the use of high frequency bands such as 28, 60 or even 140 GHz because of the large portion of spectrum that is available. Unfortunately, such mmWave links frequently change their capacity due to blocking and weather phenomena which makes it challenging to design stable multihop backhaul networks using those frequency bands. In this paper, we investigate the use of Software Defined Networking (SDN) for the operation and control of wireless backhaul networks. We explore different ways how SDN resiliency mechanisms such as FastFailover Groups can be used to mitigate disruptive connectivity in the multihop operation due to mmWave links frequently failing. We also demonstrate a clear benefit for using low frequency assist mode, where the small cell has an additional stable LTE uplink to the eNB that is used should the mmWave backhaul links fail. Our experiments using a network emulator show that such SDN based local repair mechanisms can significantly reduce the packet loss rate inside the mmWave backhaul mesh, which can be further reduced with an LTE assisted Failover.

  • 176.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    QoS Enabled WiFi MAC Layer Processing as an Example of a NFV Service2015In: Network Softwarization (NetSoft), 2015 1st IEEE Conference on, IEEE, 2015, p. 1-9Conference paper (Refereed)
  • 177.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    QoS Management for WiFi MAC layer processing in the Cloud: Demo Description2015In: Proceedings of the 11th ACM Symposium on QoS and Security for Wireless and Mobile Networks, Association for Computing Machinery (ACM), 2015, p. 173-174Conference paper (Refereed)
    Abstract [en]

    We present a demo of Quality of Service Management for CloudMAC, which combines SDN with NFV for processing WLAN MAC layer management frames in the Cloud. With CloudMAC, enterprise WLANs can be managed in the cloud which enables simple support for authentication, authorization and accounting, or mobility management. With CloudMAC, clients are associated with Virtual Machines and mobility management is simplified by updating OpenFlow forwarding rules. This enables seamless mobility. While CloudMAC works with standard WLAN clients, CloudMAC APs are very lightweight. In this demo, we show how we can manage different QoS classes in SDN enabled networks which allows a flexible WLAN MAC frame prioritisation. As an example, we implement 802.11ae based WLAN MAC management frame priorization in both the SDN network and the CloudMAC lightweight APs.

  • 178.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Resilient SDN based Small Cell Backhaul Networks using mm Wave Bands2016In: World of Wireless, Mobile and Multimedia Networks (WoWMoM), 2016 IEEE 17th International Symposium on A, IEEE, 2016Conference paper (Refereed)
  • 179.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    SDN enabled resiliency in LTE assisted small cell mmWave backhaul networks2017In: Proceedings of the 2017 20th conference on innovations in clouds, internet and networks (ICIN) / [ed] Crespi, N Manzalini, A Secci, IEEE, 2017, p. 199-202Conference paper (Refereed)
    Abstract [en]

    As mobile data usage increases dramatically, new architectures and technologies for wireless communication are required. Next generation of mobile networks are expected to be augmented by a massive amount of small cells that will be densely deployed. In order to connect the small cells, new high capacity wireless backhauling technologies are required. A promising solution is to use frequencies in the mmWave band, which allows for much greater capacity due to the massive amount of free spectrum. However, the special characteristics of the mmWave bands such as high path loss and atmospheric absorption lead to unstable links. In this paper, we investigate using Software Defined Networking principles for the operation and control of wireless backhaul networks. We demonstrate how SDN resiliency mechanisms can be used to mitigate disruptive connectivity due to mmWave links frequently failing. For assisting the small cell backhauling, we propose to also use the LTE uplinks of the small cells as backup links, should the mmWave mesh forwarding link break. Our experiments using a network emulator show that using SDN-based local repair mechanisms can significantly reduce the packet loss rate inside the mmWave backhaul mesh, which can be further reduced with an LTE assisted Failover.

  • 180.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Akerberg, Johan
    ABB Corp Res, Vasteras.
    FastReact: In-Network Control And Caching For Industrial Control Networks Using Programmable Data Planes2018In: 2018 IEEE 23RD INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA), IEEE, 2018, p. 219-226Conference paper (Refereed)
    Abstract [en]

    Providing network reliability as well as low and predictable latency is important especially for Industrial Automation and Control Networks. However, diagnosing link status from the control plane has high latency and overhead. In addition, the communication with the industrial controller may impose additional network latency. We present FastReact - a system enabling In-Network monitoring, control and caching for Industrial Automation and Control Networks. FastReact outsources simple monitoring and control actions to evolving programmable data planes using the P4 language. As instructed by the Industrial Controller through a Northbound API, the SDN controller composes control actions using Boolean Logic which are then installed in the data plane. The data plane parses and caches sensor values and performs simple calculations on them which are connected to fast control actions that are executed locally. For resiliency, FastReact monitors liveness and response of sensors/actuators and performs a fast local link repair in the data plane if a link failure is detected. Our testbed measurement show that FastReact can reduce the sensor/actuator delay while being resilient against several failure events.

  • 181.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Akerberg, Johan
    ABB Corp Res, Västerås, Sweden.
    Resilient Software Defined Networking for Industrial Control Networks2015In: 2015 10th International Conference on Information, Communications and Signal Processing (ICICS), IEEE, 2015Conference paper (Refereed)
    Abstract [en]

    Software Defined Networking (SDN) is currently a hot topic in the area of Datacenter Networking or Enterprise Networks as it has the promise to radically simplify network management and operation. However, it has not been considered so far as a promising candidate for Industrial Control Networks mainly because of the deterministic performance requirements and the dedicated design of those networks to fulfil strict performance guarantees. In this paper, we propose a resilient SDN based architecture for Industrial Control Networks and show that by combining several SDN based fast failover technologies using per-link Bidirectional Forwarding Detection (BFD), preconfigured primary and backup paths and flexible packet duplication orchestrated by an SDN controller, we can reduce significantly the control latency and provide more stringent performance guarantees even under lossy and failing links.

  • 182.
    Vestin, Jonathan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bhamare, Deval
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Andersson, Jan-Olov
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Pongracz, Gergely
    Ericsson AB, Hungrary.
    Programmable Event Detection for In-Band Network Telemetry2019Conference paper (Refereed)
    Abstract [en]

    In-Band Network Telemetry (INT) is a novel framework for collecting telemetry items and switch internal state information from the data plane at line rate. With the suppor programmable data planes and programming language P4,switches parse telemetry instruction headers and determine which telemetry items to attach using custom metadata. At the network edge, telemetry information is removed and the original packets are forwarded while telemetry reports are sent to a distributed stream processor for further processing by a network monitoring platform. In order to avoid excessive load on the stream processor, telemetry items should not be sent for each individual packet but rather when certain events are triggered. In this paper, we develop a programmable INT event detection mechanism in P4 that allows customization of which events to report to the monitoring system, on a per-flow basis, from the control plane. At the stream processor, we implement a fast INT report collector using the kernel bypass technique AF XDP, which parses telemetry reports and streams them to a distributed Kafka cluster, which can apply machine learning, visualization and further monitoring tasks. In our evaluation, we use realworld traces from different data center workloads and show that our approach is highly scalable and significantly reduces the network overhead and stream processor load due to effective event pre-filtering inside the switch data plane. While the INT report collector can process around 3 Mpps telemetry reports per core, using event pre-filtering increases the capacity by 10-15x.

  • 183.
    Zeljkovic, Ensar
    et al.
    Univ Antwerp, Belgium.
    Marquez-Barja, Johann M.
    Univ Antwerp, Belgium.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Riggio, Roberto
    FBK CREATE, NET, Italy.
    Latre, Steven
    Univ Antwerp, Belgium.
    Proactive Access Point Driven Handovers in IEEE 802.11 Networks2018In: 14th International Conference on Network and Service Management, CNSM 2018 / [ed] S. Salsano, R. Riggio, T. Ahmed, T. Samak, CRP. DosSantos, IEEE, 2018, p. 261-267Conference paper (Refereed)
    Abstract [en]

    In large and densely deployed IEEE 802.11 networks, a fast and seamless handover scheme is an important aspect in order to provide reliable connectivity for mobile users. However, IEEE 802.11 only supports decentralized, reactive and mobile node-driven handovers resulting in long handover times, packet loss due to interrupted connectivity and sub-optimal access point selection. Recently, centralized approaches have been developed that try to solve many of the challenges but these are mostly proprietary, reactive and require changes to mobile node stacks. In this paper, we propose a novel handover solution based on the principle of Software Defined Networking, that addresses the aforementioned challenges. Using virtualization and softwarization, we shift the traditional mobile node-driven handovers to the access point, while maintaining compliance with legacy devices. Moreover, we develop a proactive handover algorithm ADNA, which combines network state, traffic load and node mobility information. We evaluate our approach extensively in a testbed, showing that it outperforms existing approaches by improving the overall throughput by 116% while reducing the number of handovers by 44% on average.

  • 184.
    Zhou, Shuqiao
    et al.
    Tsinghua University.
    Yuan, Ruixi
    Tsinghua University.
    Dely, Peter
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Mitigating Control Channel Saturation in the Dynamic Channel Assignment Protocol2011In: JCIT: Journal of Convergence Information Technology, ISSN 2233-9299, Vol. 6, no 6, p. 271-281Article in journal (Refereed)
    Abstract [en]

     Multi-channel MAC protocols that rely on a dedicated control channel (CC) for data channel reservation face the problem of control channel saturation. When the control channel becomes the bottleneck, data channels are not fully utilized and the spectrum allocated for the network is not used efficiently. For a popular dedicated control channel based multi-channel MAC protocol, the dynamic channel assignment protocol (DCA), we propose and compare two methods for mitigating control channel saturation. The first method is based on the ability of modern wireless cards to use different channel bandwidths. Increasing the bandwidth of the CC allows higher transmission rates and thereby relieves the saturation on the CC. The second method involves TXOP (Transmission Opportunity)-like burst-transmissions, where several date packets are transmitted using one reservation operation on the control channel. Network simulations and analysis show that, in an 802.11 based network, the bandwidth adaptation method yields a throughput improvement of around 30%. The TXOP mechanism performs much better and increases the throughput by a factor of 2 to 10, depending on the length of the data packets.

  • 185. Zola, Enria
    et al.
    Barcelo-Arroyo, Francisco
    Dely, Peter
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Expected Bit Rate for Terminals Moving According to the Random Waypoint Model in a WLAN Cell2013Conference paper (Refereed)
    Abstract [en]

    The IEEE 802.11 standard defines the different bit rates and modulation schemes to which a WLAN device may adapt according to the channel quality. User mobility may also have an impact on the available bit rate. This paper presents a study of the bit rate evolution along time for devices that move according to the Random Waypoint mobility pattern in WLAN cells. Simulation has been applied in order to obtain statistical results that permit to characterize the evolution of the bit rate behavior along time and to compute average results in the ideal case (without interference) and in the presence of interfering devices. Our results can be useful in the solution of optimization problems in which decision on where to connect must be taken based on some minimum guaranteed bit rate. They also can be useful in the design of inter and intra-cell handover methods and load balancing schemes.

  • 186. Zola, Enrica
    et al.
    Barcelo, Francisco
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Multi-objective Optimization of WLAN Associations with Improved Handover Costs2014In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 18, no 11Article in journal (Refereed)
    Abstract [en]

    The deployment of a large number of access points in public areas presents a new paradigm in which a given station may be served by more than one access point at a time. Recently, a network model has been proposed to derive the optimal association strategy for the stations by solving a linear optimization problem. According to that model, a station cannot download data while performing a handover. In this letter, we demonstrate that, even in static conditions (i.e., no mobility and constant load in the cell), an association strategy can force a handover. We thus propose a multi-objective optimization function that maximizes the download rates and minimizes the number of handovers. As a handover implies an extra cost due to necessary signaling to be exchanged, we propose a new handover cost function that takes into account the extra bandwidth. Using the new strategy, the system throughput slightly decreases, and the number of handovers is reduced.

  • 187. Zola, Enrica
    et al.
    Dely, Peter
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Barcelo-Arroyo, Francisco
    Robust Association for Multi-radio Devices under Coverage of Multiple Networks2013Conference paper (Refereed)
  • 188. Zola, Enrica
    et al.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Energy Efficient Control of Virtual Machine Consolidation under Uncertain Input Parameters for the Cloud2015In: Proceedings of the Workshop on Engineering and Control for Reliable Cloud Services, Ghent, Belgium, September 2015, 2015Conference paper (Refereed)
  • 189.
    Zola, Enrica
    et al.
    UPC, Dept Network Engn, Barcelona, Spain.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Energy Efficient Virtual Machine Consolidation under Uncertain Input Parameters for Green Data Centers2015In: 2015 IEEE 7th International Conference on Cloud Computing Technology and Science (CloudCom), IEEE, 2015, p. 436-439Conference paper (Refereed)
    Abstract [en]

    Reducing the energy consumption of data centers and the Cloud is very important in order to lower CO2 footprint and operational cost (OPEX) of a Cloud operator. To this extent, it becomes crucial to minimise the energy consumption by consolidating the number of powered-on physical servers that host the given virtual machines (VMs). In this work, we propose a novel approach to the energy efficient VM consolidation problem by applying Robust Optimisation Theory. We develop a mathematical model as a robust Mixed Integer Linear Program under the assumption that the input to the problem (e.g. resource demands of the VMs) is not known precisely, but varies within given bounds. A numerical evaluation shows that our model allows the Cloud Operator to tradeoff between the power consumption and the protection from more severe and unlikely deviations of the uncertain input.

  • 190.
    Zola, Enrica
    et al.
    Spain.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Centre for HumanIT (from 2013).
    Minimizing the impact of the handover for mobile users in WLAN: A study on performance optimization2016In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 107, p. 292-303Article in journal (Refereed)
    Abstract [en]

    IEEE 802.11 based Wireless LANs are an important piece in today’s communication infrastructure in order to provide high speed wireless Internet access to static or quasi mobile users. For large WLAN deployments (i.e., Campus or enterprise WLAN), it is important to understand the impact of user mobility and handovers on the system performance. In this article, we have developed a performance model for a set of networked 802.11 based WLAN Access Points, which is based on a Mixed Integer Linear Program (MILP). The objective function tries simultaneously to maximize the total system rate while at the same time minimizing the number of handovers for a configurable handover signaling rate. Because of the conflicting nature of the two objective functions, such multi-objective optimization is difficult to explore. A detailed evaluation of the model using several scenarios involving both different numbers of static and mobile users shows that our formulation allows trading off those two objectives in a robust way. 

  • 191.
    Zola, Enrica
    et al.
    Universitat Politècnica de Catalunya (UPC), Barcelona.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Optimising for Energy or Robustness? Trade-off for VM Consolidation under Uncertainty2016In: Optimization Letters, ISSN 1862-4472, E-ISSN 1862-4480Article in journal (Refereed)
    Abstract [en]

    Reducing the energy consumption of virtualized datacenters and the Cloud is very important in order to lower CO2 footprint and operational cost of a Cloud operator. However, there is a trade-off between energy consumption and perceived application performance. In order to save energy, Cloud operators want to consolidate as many Virtual Machines (VM) on the fewest possible physical servers, possibly involving overbooking of resources. However, that may involve SLA violations when many VMs run on peak load. Such consolidation is typically done using VM migration techniques, which stress the network. As a consequence, it is important to find the right balance between the energy consumption and the number of migrations to perform. Unfortunately, the resources that a VM requires are not precisely known in advance, which makes it very difficult to optimise the VM migration schedule. In this paper, we therefore propose a novel approach based on the theory of robust optimisation. We model the VM consolidation problem as a robust Mixed Integer Linear Program and allow to specify bounds for e.g. resource requirements of the VMs. We show that, by using our model, Cloud operators can effectively trade-off uncertainty of resource requirements with total energy consumption. Also, our model allows us to quantify the price of the robustness in terms of energy saving against resource requirement violations.

  • 192. Zola, Enrica
    et al.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Kim, Wooseong
    Joint User Association and Energy Aware Routing for Green Small Cell mmWave Backhaul Networks2017In: 2017 IEEE Wireless Communications and Networking Conference (WCNC), IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    A dense deployment of small cells is one of the key characteristics envisioned for future 5G mobile networks in order to provide the required capacity increase. To cut cabling costs, small cells are foreseen to form multihop topologies using high capacity backhaul wireless links in the mmWave bands. Such small cells are deployed within the coverage area of a macro cell (eNB) to provide localized capacity where needed according to the well known Heterogeneous Network concept (HetNet). However, green networking will be very important because powering on unnecessarily a massive amount of small cells may lead to increased OPEX and CO2 emission. In this paper, we propose an optimization model that minimizes the total power consumption of 5G HetNets deployments while providing the required capacity and coverage. Our model jointly optimizes the user association, routing in the multihop backhaul and decides to power on or off the small cells to serve the user demands. Our numerical evaluation show significant power savings over a large range of traffic demand distributions while keeping the blocking probability low.

  • 193. Zola, Erica
    et al.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Minimizing the Impact of Handover in WLAN: A Study on Performance Optimization2015In: Proceedings of SWE-CTW 2015, May 27th – 29th, Karlstad, Sweden, 2015Conference paper (Refereed)
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