• A Fault-Tolerant and Consistent SDN Controller 

      Kamisinski, Andrzej; Gonzalez, Andres Javier; Helvik, Bjarne Emil; Nencioni, Gianfranco (Chapter; Conference object; Peer reviewed, 2016)
      Software-Defined Networking (SDN) is a new paradigm that promises to enhance network flexibility and innovation. However, operators need to thoroughly assess its advantages and threats before they can implement it. Robustness ...
    • A modeling approach for dependability analysis of smart distribution grids 

      Zerihun, Tesfaye Amare; Helvik, Bjarne Emil; Heegaard, Poul Einar (Chapter, 2018)
      The distribution grids are among the most critical infrastructures which integrates advanced control and communication technologies atop of power systems. This paper presents a comprehensive modeling framework suited to ...
    • Achieving dependability in software-defined networking - a perspective 

      Helvik, Bjarne Emil; Heegaard, Poul Einar; Mendiratta, Veena (Chapter; Conference object; Peer reviewed, 2015)
      In this paper we take a closer look at the operationof software defined networking (SDN) in intra-domain networks.The focus is on the dependability issues related to interworking ofSDN controllers, network OS (NOS), and ...
    • An Empirical Study of Software Reliability in SDN Controllers 

      Vizarreta, Petra; Trivedi, Kishor; Helvik, Bjarne Emil; Heegaard, Poul Einar; Kellerer, Wolfgang; Mas Machuca, Carmen (Chapter, 2017)
      Software Defined Networking (SDN) exposes critical networking decisions, such as traffic routing or enforcement of the critical security policies, to a software entity known as the SDN controller. Controller software, as ...
    • Analysis of the effect of InfoRanking on content pollution in peer-to-peer systems 

      Zhang, Peiqing; Fotiou, Nikos; Helvik, Bjarne Emil; Marias, Giannis F.; Polyzos, George C. (Journal article; Peer reviewed, 2014)
      Content pollution is one of the most common attacks against peer-to-peer file-sharing systems. As such, systems are usually open to users, and the deployed security mechanisms merely examine the sanity of the downloaded ...
    • Assessing the maturity of SDN controllers with software reliability growth models 

      Vizarreta, Petra; Trivedi, Kishor; Helvik, Bjarne Emil; Heegaard, Poul Einar; Blenk, Andreas; Kellerer, Wolfgang; Mas Machuca, Carmen (Journal article; Peer reviewed, 2018)
      In software defined networking (SDN), critical control plane functions are offloaded to a software entity known as the SDN controller. Today's SDN controllers are complex software systems, owing to heterogeneity of networks ...
    • Assessing the risk of violating SLA dependability requirements in software-defined networks 

      Kamisiński, Andrzej; Helvik, Bjarne Emil; Gonzalez, Andres Javier; Nencioni, Gianfranco (Chapter; Peer reviewed, 2017)
      Dependability of computer and communication networks is an important aspect of the customer-provider relationship in the telecommunication industry. Considering the increasing interest in Software-Defined Networking (SDN) ...
    • Availability Modelling of Software-Defined Backbone Networks 

      Kamisinski, Andrzej; Gonzalez, Andres Javier; Helvik, Bjarne Emil; Nencioni, Gianfranco; Heegaard, Poul Einar (Chapter; Conference object; Peer reviewed, 2016)
      Software-Defined Networking (SDN) promises to improve the programmability and flexibility of networks, but it may also bring new challenges that need to be explored. The main objective of this paper is to present a ...
    • Banken i skyen - fremtidige trender og scenarioer for skytjenester i banksektoren 

      Jeyaseelan, Sutharsan (Master thesis, 2014)
      Bruk av finansielle tjenester er sterkt utbredt i dagens moderne samfunn. Den finansielle infrastrukturen i Norge prosesserte i 2013 daglig et gjennomsnitt på 203 milliarder kroner. Mens andre sektorer og industrier ...
    • Cost comparison studies of different network platforms: OpEx modeling and analysis 

      Moe, Øyvind Solberg (Master thesis, 2007)
      The importance of Operational Expenditures (OpEx) on the overall network cost has been shown in recent studies. This master thesis is part of a series of techno economical studies focused on the evaluation of OpEx and the ...
    • Dependability Analysis of Smart Distribution Grid Architectures Considering Various Failure Modes 

      Zerihun, Tesfaye Amare; Helvik, Bjarne Emil (Chapter, 2018)
      The future smart distribution grid will be consisting of new components and technologies with enhanced capability whose failure behaviour can not be determined with certainty. In studying the reliability of these distribution ...
    • Dependability modelling of Jgroup/ARM 

      Sæstad, Ane (Master thesis, 2008)
      In the later years, fault tolerant distributed systems have been applied to a variety of network internal and external services. Keeping distributed systems consistent and fault tolerant require management functionality. ...
    • Dependability of the NFV Orchestrator: State of the Art and Research Challenges 

      Gonzalez, Andres Javier; Nencioni, Gianfranco; Kamisinski, Andrzej; Helvik, Bjarne Emil; Heegaard, Poul Einar (Journal article; Peer reviewed, 2018)
      The introduction of network function virtualisation (NFV) represents a significant change in networking technology, which may create new opportunities in terms of cost efficiency, operations, and service provisioning. ...
    • Design and Implementation of an Efficient, Reliable and Safe Work-Package Database System at CERN 

      Riksem, Hans-Even Ramsevik (Master thesis, 2010)
      The Activity Coordination Tool (ACT) is a web application designed to automate theplanning and coordination of work packages. In the CMS experiment at CERN it isimportant that work packages in the underground facilities ...
    • Evaluating Local Disaster Recovery Strategies 

      Oostenbrink, Jorik; Kuipers, Fernando; Heegaard, Poul Einar; Helvik, Bjarne Emil (Journal article; Peer reviewed, 2018)
    • Evaluating Quality of Experience in Videoconferencing Systems Based on Packet Loss 

      Kvistad, Ole Martin (Master thesis, 2008)
      Users of multimedia applications get more and more quality aware as the development of technologies progresses. When looking at videoconferencing it would be a great advantage knowing what level of quality a user experiences ...
    • Failure analysis and prediction in compound system by wavelets 

      Zerihun, Tesfaye Amare (Master thesis, 2016)
      The current overall ICT infrastructure mainly the Internet and Telecom networks can be looked upon as an ecosystem, which is the result of the cooperation between a huge number of Autonomous systems (ASes). The interconnection ...
    • Failure Process Characteristics of Cloud-Enabled Services 

      Tola, Besmir; Jiang, Yuming; Helvik, Bjarne Emil (Chapter; Peer reviewed, 2017)
      The design of cloud computing technologies need to guarantee high levels of availability and for this reason there is a large interest in new fault tolerant techniques that are able to keep the resilience of the systems ...
    • Fulfilling efficiently SLA availability guarantees in backbone networks 

      Tiwari, Prakriti (Master thesis, 2014)
      The availability and reliability of backbone networks is important tosociety. However, physical, software and unintentional human errorfailures affect the links and nodes in a backbone network. To overcomesuch failures in ...
    • GEARSHIFT: Guaranteeing availability requirements in SLAs using hybrid fault tolerance 

      Gonzalez, Andres Javier; Helvik, Bjarne Emil; Tiwari, Prakriti; Denis, Becker; Wittner, Otto Jonassen (Chapter; Conference object; Peer reviewed, 2015)
      The dependability of ICT systems is vital for today's society. However, operational systems are not fault free. Providers and customers have to define clear availability requirements and penalties on the delivered services ...