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  • 1.
    Adam, Constantin
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Stadler, Rolf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A Middleware Design for Large-scale Clusters offering Multiple Services2006In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 3, no 1, p. 1-12Article in journal (Refereed)
    Abstract [en]

    We present a decentralized design that dynamically allocates resources to multiple services inside a global server cluster. The design supports QoS objectives (maximum response time and maximum loss rate) for each service. A system administrator can modify policies that assign relative importance to services and, in this way, control the resource allocation process. Distinctive features of our design are the use of an epidemic protocol to disseminate state and control information, as well as the decentralized evaluation of utility functions to control resource partitioning among services. Simulation results show that the system operates both effectively and efficiently; it meets the QoS objectives and dynamically adapts to load changes and to failures. In case of overload, the service quality degrades gracefully, controlled by the cluster policies.

  • 2.
    Adam, Constantin
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Service middleware for self-managing large-scale systems2007In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 4, no 3, p. 50-64Article in journal (Refereed)
    Abstract [en]

    Resource management poses particular challenges in large-scale systems, such as server clusters that simultaneously process requests from a large number of clients. A resource management scheme for such systems must scale both in the in the number of cluster nodes and the number of applications the cluster supports. Current solutions do not exhibit both of these properties at the same time. Many are centralized, which limits their scalability in terms of the number of nodes, or they are decentralized but rely on replicated directories, which also reduces their ability to scale. In this paper, we propose novel solutions to request routing and application placementtwo key mechanisms in a scalable resource management scheme. Our solution to request routing is based on selective update propagation, which ensures that the control load on a cluster node is independent of the system size. Application placement is approached in a decentralized manner, by using a distributed algorithm that maximizes resource utilization and allows for service differentiation under overload. The paper demonstrates how the above solutions can be integrated into an overall design for a peer-to-peer management middleware that exhibits properties of self-organization. Through complexity analysis and simulation, we show to which extent the system design is scalable. We have built a prototype using accepted technologies and have evaluated it using a standard benchmark. The testbed measurements show that the implementation, within the parameter range tested, operates efficiently, quickly adapts to a changing environment and allows for effective service differentiation by a system administrator.

  • 3.
    Dan, Jurca
    et al.
    NTT DOCOMO Eurolabs in Munich, Germany.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES).
    H-GAP: Estimating Histograms of Local Variables with Accuracy Objectives for Distributed Real-Time Monitoring2010In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 7, no 2, p. 83-95Article in journal (Refereed)
    Abstract [en]

    We present H-GAP, a protocol for continuous monitoring,which provides a management station with the valuedistribution of local variables across the network. The protocolestimates the histogram of local state variables for a givenaccuracy and with minimal overhead. H-GAP is decentralizedand asynchronous to achieve robustness and scalability, and itexecutes on an overlay interconnecting management processesin network devices. On this overlay, the protocol maintains aspanning tree and updates the histogram through incrementalaggregation. The protocol is tunable in the sense that it allowscontrolling, at runtime, the trade-off between protocol overheadand an accuracy objective. This functionality is realized throughdynamic configuration of local filters that control the flow ofupdates towards the management station. The paper includes ananalysis of the problem of histogram aggregation over aggregationtrees, a formulation of the global optimization problem, anda distributed solution containing heuristic, tree-based algorithms.Using SUM as an example, we show how general aggregationfunctions over local variables can be efficiently computed withH-GAP. We evaluate our protocol through simulation using realtraces. The results demonstrate the controllability of H-GAP ina selection of scenarios and its efficiency in large-scale networks.

  • 4.
    Fetahi, Wuhib
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Dam, Mads
    KTH, School of Computer Science and Communication (CSC), Theoretical Computer Science, TCS.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Alexander, Clemm
    Cisco Systems, San Jose, CA USA.
    Robust Monitoring of Network-wide Aggregates through Gossiping2009In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 6, no 2, p. 95-109Article in journal (Refereed)
    Abstract [en]

    We investigate the use of gossip protocols for continuousmonitoring of network-wide aggregates under crash failures.Aggregates are computed from local management variablesusing functions such as SUM, MAX, or AVERAGE. For this typeof aggregation, crash failures offer a particular challenge dueto the problem of mass loss, namely, how to correctly accountfor contributions from nodes that have failed. In this paper wegive a partial solution. We present G-GAP, a gossip protocolfor continuous monitoring of aggregates, which is robust againstfailures that are discontiguous in the sense that neighboringnodes do not fail within a short period of each other. We giveformal proofs of correctness and convergence, and we evaluatethe protocol through simulation using real traces. The simulationresults suggest that the design goals for this protocol have beenmet. For instance, the tradeoff between estimation accuracyand protocol overhead can be controlled, and a high estimationaccuracy (below some 5% error in our measurements) is achievedby the protocol, even for large networks and frequent nodefailures. Further, we perform a comparative assessment of GGAPagainst a tree-based aggregation protocol using simulation.Surprisingly, we find that the tree-based aggregation protocolconsistently outperforms the gossip protocol for comparativeoverhead, both in terms of accuracy and robustness.

  • 5.
    Fischer, Andreas
    et al.
    University of Passau.
    De Meer, Hermann
    University of Passau.
    Generating Virtual Network Embedding Problems with Guaranteed Solutions2016In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 13, no 3, p. 504-517Article in journal (Refereed)
    Abstract [en]

    The efficiency of network virtualization depends on the appropriate assignment of resources. The underlying problem, called Virtual Network Embedding, has been much discussed in the literature, and many algorithms have been proposed, attempting to optimize the resource assignment in various respects. Evaluation of those algorithms requires a large number of randomly generated embedding scenarios. This paper presents a novel scenario generation approach and demonstrates how to produce scenarios with a guaranteed exact solution, thereby facilitating better evaluation of embedding algorithms.

  • 6.
    Franke, Ulrik
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Optimal IT service availability: Shorter outages, or fewer?2012In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 9, no 1, p. 22-33Article in journal (Refereed)
    Abstract [en]

    High enterprise IT service availability is a key success factor throughout many industries. While understanding of the economic importance of availability management is becoming more widespread, the implications for management of Service Level Agreements (SLAs) and thinking about availability risk management are just beginning to unfold. This paper offers a framework within which to think about availability management, highlighting the importance of variance of outage costs. The importance of variance is demonstrated using simulations on existing data sets of revenue data. An important implication is that when outage costs are proportional to outage duration, more but shorter outages should be preferred to fewer but longer, in order to minimize variance. Furthermore, two archetypal cases where the cost of an outage depends non-linearly on its duration are considered. An optimal outage length is derived, and some guidance is also given for its application when the variance of hourly downtime costs is considered. The paper is concluded with a discussion about the feasibility of the method, its practitioner relevance and its implications for SLA management.

  • 7.
    Franke, Ulrik
    et al.
    KTH, School of Electrical Engineering (EES). SICS, Sweden.
    Buschle, Markus
    KTH, School of Electrical Engineering (EES). Zeb Consulting, Sweden.
    Experimental Evidence on Decision-Making in Availability Service Level Agreements2016In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 13, no 1, p. 58-70Article in journal (Refereed)
    Abstract [en]

    As more enterprises buy information technology services, studying their underpinning contracts becomes more important. With cloud computing and outsourcing, these service level agreements (SLAs) are now often the only link between the business and the supporting IT services. This paper presents an experimental economics investigation of decision-making with regard to availability SLAs, among enterprise IT professionals. The method and the ecologically valid subjects make the study unique to date among IT service SLA studies. The experiment consisted of pairwise choices under uncertainty, and subjects (N = 46) were incentivized by payments based on one of their choices, randomly selected. The research question investigated in this paper is: Do enterprise IT professionals maximize expected value when procuring availability SLAs, as would be optimal from the business point of view? The main result is that enterprise IT professionals fail to maximize expected value. Whereas some subjects do maximize expected value, others are risk-seeking, risk-averse, or exhibit non-monotonic preferences. The nonmonotonic behavior in particular is an interesting observation, which has no obvious explanation in the literature. For a subset of the subjects (N = 29), a few further hypotheses related to associations between general attitude to risk or professional experience on the one hand, and behavior in SLAs on the other hand, were investigated. No support for these associations was found. The results should be interpreted with caution, due to the limited number of subjects. However, given the prominence of SLAs in modern IT service management, the results are interesting and call for further research, as they indicate that current professional decision-making regarding SLAs can be improved. In particular, if general attitude to risk and professional experience do not impact decision-making with regard to SLAs, more extensive use of decision-support systems might be called for in order to facilitate proper risk management.

  • 8.
    Franke, Ulrik
    et al.
    RISE, Swedish ICT, SICS, Software and Systems Engineering Laboratory. KTH Royal Institute of Technology, Sweden.
    Buschle, Markus
    KTH Royal Institute of Technology, Sweden; Zeb/Consulting, Sweden.
    Experimental Evidence on Decision-Making in Availability Service Level Agreements2016In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 13, no 1, p. 58-70, article id 7360206Article in journal (Refereed)
    Abstract [en]

    As more enterprises buy information technology services, studying their underpinning contracts becomes more important. With cloud computing and outsourcing, these service level agreements (SLAs) are now often the only link between the business and the supporting IT services. This paper presents an experimental economics investigation of decision-making with regard to availability SLAs, among enterprise IT professionals. The method and the ecologically valid subjects make the study unique to date among IT service SLA studies. The experiment consisted of pairwise choices under uncertainty, and subjects (N=46) were incentivized by payments based on one of their choices, randomly selected. The research question investigated in this paper is: Do enterprise IT professionals maximize expected value when procuring availability SLAs, as would be optimal from the business point of view? The main result is that enterprise IT professionals fail to maximize expected value. Whereas some subjects do maximize expected value, others are risk-seeking, risk-averse, or exhibit nonmonotonic preferences. The nonmonotonic behavior in particular is an interesting observation, which has no obvious explanation in the literature. For a subset of the subjects (N=29), a few further hypotheses related to associations between general attitude to risk or professional experience on the one hand, and behavior in SLAs on the other hand, were investigated. No support for these associations was found. The results should be interpreted with caution, due to the limited number of subjects. However, given the prominence of SLAs in modern IT service management, the results are interesting and call for further research, as they indicate that current professional decision-making regarding SLAs can be improved. In particular, if general attitude to risk and professional experience do not impact decision-making with regard to SLAs, more extensive use of decision-support systems might be called for in order to facilitate proper risk management.

  • 9.
    Gao, Deyun
    et al.
    School of Electronic and Information Engineering, Beijing Jiaotong University.
    Rao, Ying
    China Academy of Electronics and Information Technology, Beijing.
    Foh, Huang Chen
    5GIC, Institute for Communication Systems, Department of Electrical and Electronic Engineering, University of Surrey.
    Zhang, Hongke
    School of Electronic and Information Engineering, Beijing Jiaotong University.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    PMNDN: Proxy Based Mobility Support Approach in Mobile NDN Environment2017In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 14, no 1, p. 191-203Article in journal (Refereed)
    Abstract [en]

    In this paper, we study the source mobility problem that exists in the current named data networking (NDN) architecture and propose a proxy-based mobility support approach named PMNDN to overcome the problem. PMNDN proposes using a proxy to efficiently manage source mobility. Besides, functionalities of the NDN access routers are extended to track the mobility status of a source and signal Proxy about a handoff event. With this design, a mobile source does not need to participate in handoff signaling which reduces the consumption of limited wireless bandwidth. PMNDN also features an ID that is structurally similar to the content name so that routing scalability of NDN architecture is maintained and addressing efficiency of Interest packets is improved. We illustrate the performance advantages of our proposed solution by comparing the handoff performance of the mobility support approaches with that in NDN architecture and current Internet architecture via analytical and simulation investigation. We show that PMNDN offers lower handoff cost, shorter handoff latency, and less packet losses during the handoff process

  • 10.
    Ibidunmoye, Olumuyiwa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Ali-Reza, Rezaie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Adaptive Anomaly Detection in Performance Metric Streams2018In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 15, no 1, p. 217-231Article in journal (Refereed)
    Abstract [en]

    Continuous detection of performance anomalies such as service degradations has become critical in cloud and Internet services due to impact on quality of service and end-user experience. However, the volume and fast changing behaviour of metric streams have rendered it a challenging task. Many diagnosis frameworks often rely on thresholding with stationarity or normality assumption, or on complex models requiring extensive offline training. Such techniques are known to be prone to spurious false-alarms in online settings as metric streams undergo rapid contextual changes from known baselines. Hence, we propose two unsupervised incremental techniques following a two-step strategy. First, we estimate an underlying temporal property of the stream via adaptive learning and, then we apply statistically robust control charts to recognize deviations. We evaluated our techniques by replaying over 40 time-series streams from the Yahoo! Webscope S5 datasets as well as 4 other traces of real web service QoS and ISP traffic measurements. Our methods achieve high detection accuracy and few false-alarms, and better performance in general compared to an open-source package for time-series anomaly detection.

  • 11.
    Javier, Baliosian
    et al.
    Ericsson Ireland Research Centre, Athlone, Ireland.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Distributed Auto-configuration of Neighboring Cell Graphs in Radio Access Networks2010In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 7, no 3, p. 145-157Article in journal (Refereed)
    Abstract [en]

    In order to execute a handover processes in a GSMor UMTS Radio Access Network, each cell has a list of neighborsto which such handovers may be made. Today, these lists arestatically configured during network planning, which does notallow for dynamic adaptation of the network to changes andunexpected events such as a cell failure. This paper advocatesan autonomic, decentralized approach to dynamically configureneighboring cell lists. The main contribution of this work isa novel protocol, called DOC, which detects and continuouslytracks the coverage overlaps among cells. The protocol executeson a spanning tree where the nodes are radio base stations andthe links represent communication channels. Over this tree, nodesperiodically exchange information about terminals that are intheir respective coverage area. Bloom filters are used for efficientrepresentations of terminal sets and efficient set operations. Theprotocol aggregates Bloom filters to reduce the communicationoverhead and also for routing messages along the tree. Usingsimulation, we study the system in steady state, when a basestation is added or a base station fails, and also during theinitialization phase where the system self-configures.

  • 12. Kristiansson, Johan
    et al.
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    An application-layer approach to seamless mobile multimedia communication2006In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 3, no 1, p. 33-42Article in journal (Refereed)
    Abstract [en]

    Providing seamless IP mobility support is one of the most challenging problems towards a world of mobile and ubiquitous multimedia communication. This paper proposes an application-layer framework based on the Session Initiation Protocol and the Resilient Mobile Socket to provide mobility support for distributed multimedia applications. As a part of the framework the paper describes a new handover strategy called Competition-based Soft-Handover Management that uses simulcast to improve quality of service and to seamlessly hand over multimedia traffic to the network interface that currently offers better network characteristics. In short, during a handover packets are simulcasted through all available network interfaces, and when the packets are received by the remote end-point, they are merged back into one stream. As each network connection competes with other connections in contributing to the merged stream at the remote end-point, the handover process can be viewed as a competition where the connection that contributes most is selected after the handover. As a proof of concept, the framework has been integrated into Marratech, which is a commercially available audio/video group communication application. By using network emulators, the paper demonstrates how the framework can be used to improve QoS, compare end-to-end performance, and perform lossless handovers while reducing redundant packets.

  • 13.
    Lin, Bing
    et al.
    College of Mathematics and Computer Sciences, Fuzhou University.
    Guo, Wenzhong
    College of Mathematics and Computer Sciences, Fuzhou University.
    Xiong, Naixue
    School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology.
    Chen, Guolong
    College of Mathematics and Computer Sciences, Fuzhou University.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Zhang, Hong
    College of Mathematics and Computer Sciences, Fuzhou University.
    A Pretreatment Workflow Scheduling Approach for Big Data Applications in Multi-cloud Environments2016In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 13, no 3, p. 581-594Article in journal (Refereed)
    Abstract [en]

    The rapid development of the latest distributed computing paradigm, i.e., cloud computing, generates a highly fragmented cloud market composed of numerous cloud providers and offers tremendous parallel computing ability to handle Big Data problems. One of the biggest challenges in Multi-clouds is efficient workflow scheduling. Although the workflow scheduling problem has been studied extensively, there are still very few primal works tailored for Multi-cloud environments. Moreover, the existing research works either fail to satisfy the Quality of Service (QoS) requirements, or do not consider some fundamental features of cloud computing such as heterogeneity and elasticity of computing resources. In this paper, a scheduling algorithm which is called Multi-Clouds Partial Critical Paths with Pretreatment (MCPCPP) for Big Data workflows in Multi-clouds is presented. This algorithm incorporates the concept of Partial Critical Paths, and aims to minimize the execution cost of workflow while satisfying the defined deadline constraint. Our approach takes into considerations the essential characteristics of Multi-clouds such as the charge per time interval, various instance types from different cloud providers as well as homogeneous intra-bandwidth vs. heterogeneous inter-bandwidth. Various types of workflows are used for evaluation purpose and our experimental results show that the MCPCPP is promising.

  • 14.
    Meng, Weizhi
    et al.
    Department of Applied Mathematics and Computer Science, Technical University of Denmark, Denmark.
    Raymond Choo, Kim-Kwang
    Department of Information Systems and Cyber Security and the Department of Electrical and Computer Engineering, The University of Texas at San Antonio, San Antonio, United States.
    Furnell, Steven
    School of Computing, Electronics and Mathematics, Plymouth University, United Kindom.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Probst, Christian W.
    Unitec Institute of Technology, New Zealand.
    Towards Bayesian-based Trust Management for Insider Attacks in Healthcare Software-Defined Networks2018In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 15, no 2, p. 761-773Article in journal (Refereed)
    Abstract [en]

    The medical industry is increasingly digitalized and Internet-connected (e.g., Internet of Medical Things), and when deployed in an Internet of Medical Things environment, software-defined networks (SDN) allow the decoupling of network control from the data plane. There is no debate among security experts that the security of Internet-enabled medical devices is crucial, and an ongoing threat vector is insider attacks. In this paper, we focus on the identification of insider attacks in healthcare SDNs. Specifically, we survey stakeholders from 12 healthcare organizations (i.e., two hospitals and two clinics in Hong Kong, two hospitals and two clinics in Singapore, and two hospitals and two clinics in China). Based on the survey findings, we develop a trust-based approach based on Bayesian inference to figure out malicious devices in a healthcare environment. Experimental results in either a simulated and a real-world network environment demonstrate the feasibility and effectiveness of our proposed approach regarding the detection of malicious healthcare devices, i.e., our approach could decrease the trust values of malicious devices faster than similar approaches.

  • 15.
    Steinert, Rebecca
    et al.
    SICS.
    Gillblad, Daniel
    SICS.
    Direct In-Network Localization of Performance DegradationsIn: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537Article in journal (Other academic)
  • 16.
    Wang, Yufeng
    et al.
    Nanjing University of Posts and Telecommunications, Nanjing.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Ma, Jianhua
    Hosei University, Tokyo.
    VPEF: A simple and effective incentive mechanism in community-based autonomous networks2015In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 12, no 1, p. 75-86, article id 7029119Article in journal (Refereed)
    Abstract [en]

    This paper focuses on incentivizing cooperative behavior in community-based autonomous networking environments (like mobile social networks, etc.), in which through dynamically forming virtual and/or physical communities, users voluntarily participate in and contribute resources (or provide services) to the community while consuming. Specifically, we proposed a simple but effective EGT (Evolutionary Game Theory)-based mechanism, VPEF (Voluntary Principle and round-based Entry Fee), to drive the networking environment into cooperative. VPEF builds incentive mechanism as two simple system rules: The first is VP meaning that all behaviors are voluntarily conducted by users: Users voluntarily participate (after paying round-based entry fee), voluntarily contribute resource, and voluntarily punish other defectors (incurring extra cost to those so-called punishers); The second is EF meaning that an arbitrarily small round-based entry fee is set for each user who wants to participate in the community. We presented a generic analytical framework of evolutionary dynamics to model VPEF scheme, and theoretically proved that VPEF scheme's efficiency loss defined as the ratio of system time, in which no users will provide resource, is 4/(8 + M). M is the number of users in community-based collaborative system. Finally, the simulated results using content availability as an example verified our theoretical analysis

  • 17.
    Wuhib, Fetahi
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Dam, Mads
    KTH, School of Computer Science and Communication (CSC), Theoretical Computer Science, TCS.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Communication Networks.
    A Gossiping Protocol for Detecting Global Threshold Crossings2010In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 7, no 1, p. 42-57Article in journal (Refereed)
    Abstract [en]

    We investigate the use of gossip protocols for the detection of network-wide threshold crossings. Our design goals are low protocol overhead, small detection delay, low probability of false positives and negatives, scalability, robustness to node failures and controllability of the trade-off between overhead and detection delay. Based on push-synopses, a gossip protocol introduced by Kempe et al., we present a protocol that indicates whether a global aggregate of static local values is above or below a given threshold. For this protocol, we prove correctness and show that it converges to a state with no overhead when the aggregate is sufficiently far from the threshold. Then, we introduce an extension we call TG-GAP, a protocol that (1) executes in a dynamic network environment where local values change and (2) implements hysteresis behavior with upper and lower thresholds. Key elements of its design are the construction of snapshots of the global aggregate for threshold detection and a mechanism for synchronizing local states, both of which are realized through the underlying gossip protocol. Simulation studies suggest that TG-GAP is efficient in that the protocol overhead is minimal when the aggregate is sufficiently far from the threshold, that its overhead and the detection delay are largely independent on the system size, and that the tradeoff between overhead and detection quality can be effectively controlled. Lastly, we perform a comparative evaluation of TG-GAP against a tree-based protocol. We conclude that, for detecting global threshold crossings in the type of scenarios investigated, the tree-based protocol incurs a significantly lower overhead and a smaller detection delay than a gossip protocol such as TG-GAP.

  • 18.
    Wuhib, Fetahi
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Spreitzer, Mike
    IBM T.J. Watson Research Center.
    A Gossip Protocol for Dynamic ResourceManagement in Large Cloud Environments2012In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 9, no 2, p. 213-225Article in journal (Refereed)
    Abstract [en]

    We address the problem of dynamic resource management for a large-scale cloud environment. Our contribution includes outlining a distributed middleware architecture and presenting one of its key elements: a gossip protocol that (1) ensures fair resource allocation among sites/applications, (2) dynamically adapts the allocation to load changes and (3) scales both in the number of physical machines and sites/applications. We formalize the resource allocation problem as that of dynamically maximizing the cloud utility under CPU and memory constraints. We first present a protocol that computes an optimalsolution without considering memory constraints and prove correctness and convergence properties. Then, we extend that protocol to provide an efficient heuristic solution for the complete problem, which includes minimizing the cost for adapting an allocation. The protocol continuously executes on dynamic, local input and does not require global synchronization, as other proposed gossip protocols do. We evaluate the heuristic protocol through simulation and find its performance to be well-aligned with our design goals.

  • 19.
    Yaghoubi, Forough
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS.
    Furdek, Marija
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS.
    Rostami, Ahmad
    Ericsson Res, Networks Orchestrat & Automat, S-16483 Kista, Sweden..
    Ohlen, Peter
    Ericsson Res, S-16483 Kista, Sweden..
    Wosinska, Lena
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Consistency-Aware Weather Disruption-Tolerant Routing in SDN-Based Wireless Mesh Networks2018In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 15, no 2, p. 582-595Article in journal (Refereed)
    Abstract [en]

    Wireless network solutions, a dominant enabling technology for the backhaul segment, are susceptible to weather disturbances that can substantially degrade network throughput and/or delay, compromising the stringent 5G requirements. These effects can be alleviated by centralized rerouting realized by software defined networking architecture. However, careless frequent reconfigurations can lead to inconsistencies in the network states due to asynchrony between different switches, which can create congestion and limit the rerouting gain. The aim of this paper is to minimize the total data loss during rain disturbance by proposing an algorithm that decides on the timing, the sequence, and the paths for rerouting of network flows considering the imposed congestion during reconfiguration. At each time sample, the central controller decides whether to adopt the optimal routes at a switching cost, defined as the imposed congestion, or to keep using existing, sub-optimal routes at a throughput loss. To find optimal solutions with minimal data loss in a static scenario, we formulate a dynamic programming problem that utilizes perfect knowledge of rain attenuation for the whole rain period. For dynamic scenarios with unknown future rain attenuation, we propose an online consistency-aware rerouting algorithm, called consistency-aware rerouting with prediction (CARP), which uses the temporal correlation of rain fading to estimate future rain attenuation. Simulation results on synthetic and real networks validate the efficiency of our CARP algorithm, substantially reducing data loss and increasing network throughput with a fewer number of rerouting actions compared to a greedy and a regular rerouting benchmarking approaches.

  • 20.
    Zhao, Peiyue
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Dán, György
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    A Benders Decomposition Approach for Resilient Placement of Virtual Process Control Functions in Mobile Edge Clouds2018In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 15, no 4, p. 1460-1472Article in journal (Refereed)
    Abstract [en]

    Replacing hardware controllers with software-based virtual process control functions (VPFs) is a promising approach for improving the operational efficiency and flexibility of industrial control systems. VPFs can be executed in edge clouds in 5G mobile networks or in the wireless backhaul, which can further improve efficiency. Nonetheless, for the acceptance of virtualization in industrial control systems, a fundamental challenge is to ensure that the placement of VPFs be resilient to component failures and cyber-attacks, besides being efficient. In this paper we address this challenge by considering that VPF placement costs are incurred by reserving mobile edge computing (MEC) resources, executing VPF instances, and by data communication. We formulate the VPF placement problem as an integer programming problem, considering resilience as a constraint. We propose a solution based on generalized Benders decomposition and based on linear relaxation of the resulting sub-problems, which effectively reduces the number of integer variables to the number of MEC nodes. We evaluate the proposed solution with respect to operational cost, efficiency, and scalability in a simulated metropolitan area. Our results show that the proposed solution reduces the total cost significantly compared to a greedy baseline algorithm and a local search heuristic, and can scale to moderate problem instances.

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