Harald Øverby is the Special Advisor for AI & Technology at BI Norwegian Business School. In the period 2022–2024, he was the Provost with responsibilities for Research, Learning, and Impact. Prior to joining BI in 2022, Øverby was employed at the Norwegian University of Science and Technology (NTNU) for over 20 years. His academic interests include digital economics, Internet law and regulations, communication technology, Internet architectures, and cybersecurity. He holds a MSc in Computer Science, PhD in Optical Networking, and BSc in Economics, all from NTNU. He has also studied Law at the University of Oslo. Øverby has published over 100 academic papers, including two textbooks on Digital Economics. He has taught and developed university courses for more than 20 years and been a part of study program development for both Norwegian and international study programs. He has conducted several international stays at e.g., Eurecom (France), Chalmers (Sweden), and CityU (Hong Kong).
Publications
Lønsethagen, Håkon; Lange, Stanislav, Zinner, Thomas, Øverby, Harald, Contreras, Luis M., Ciulli, Nicola & Dotaro, Emmanuel (2023)
Toward Smart Public Interconnected Networks and Services — Approaching the Stumbling Blocks
The visions of 5G and Beyond (B5G) imply unprecedented expectations toward high-performing connectivity services in both public and private networks. Connectivity services that offer performance guarantees along multiple Quality of Service (QoS) dimensions are partially available today, but are confined to (virtual) private network services. However, open and equal access to public and Internet-scale Specialized Connectivity Services (SCS) delivered on-demand does not exist. This is especially true for interconnections across networks and support for mixed traffic modes that go beyond traditional best-effort. In this article, we argue that this is a huge industrial and societal problem that needs a solution. However, this problem is highly complex and multi-faceted, and there are many reasons why we are essentially locked into the status quo. We identify the stumbling blocks and propose a set of solution elements to take us across these hurdles, alongside related research topics. This includes an approach to “Multi-Level Best-Effort (MLBE)” and suggestions for evolving net neutrality regulation. Models and simulations show how a mixed traffic mode approach provides anticipated benefits, and we provide arguments why the context brought by B5G will put us into conditions for change, allowing public SCS eventually at a global scale.
Kianpour, Mazaher; Kowalski, Stewart James & Øverby, Harald (2022)
Advancing the concept of cybersecurity as a public good
This paper presents an agent-based model of cybersecurity as a participatory public good. Ineffective cybersecurity measures pose serious threats and risks to the development and stability of information societies in the world. Various doctrines and thesis explore how this domain should be treated by the public and private stakeholders. One of these doctrines is cybersecurity as a public good. In this paper, we highlight divergent views about the type of cybersecurity as an economic good. Then, the paper proposes an agent-based simulation model of a repeated public goods game among a set of defenders that are in an uncertain environment with incomplete and imperfect information. In the model, defenders have a probability to choose contribution or being a free-rider, depending on their own preferences and facing with revealed preferences of other defenders. This model implements a utility maximization that applies to each individual, modeling the existence of free-riders, punishments, and interdependency of decisions under a polycentric governance structure. The results of this simulation model show that, over time, defenders update their preferences in reaction to the behavior of other defenders and the experience of cyber-attacks. They indicate a high level of contribution to the provision of cybersecurity as a public good and the effectiveness of decentralized punishment on increasing the contributions. The consistency of the pattern of our results across different empirical studies lends us some reassurance that our model behavior is in quantitative agreement with empirical macro-structures. Furthermore, implementation of a polycentric structure challenges all the relevant agents to take action, and provides more robust environment.
Øverby, Harald; Audestad, Jan Arild & Szalkowski, Gabriel (2022)
Compartmental market models in the digital economy—extension of the Bass model to complex economic systems
Compartmental models are widely used in epidemiology, engineering, and physics to describe the temporal behavior of complex systems. This paper presents how compartmental models may be applied to the digital economy—more specifically, how the Bass model can be extended to more complex economics systems such as markets with customer churning, competition, multisided platforms, and online games. It is demonstrated that it is straightforward to establish the equations describing the various economic systems under study, however, the equations are often too complex to be solved analytically in the general case. Though the paper presents simple and idealized cases, the solutions may, nevertheless, uncover important strategic aspects that otherwise may be hidden by complexity in the general case, for example, the reasons for slow initial market growth. The paper also discusses how the developed models may be used to evaluate digital economic market evolution and business policy.
Kianpour, Mazaher; Kowalski, Stewart James & Øverby, Harald (2021)
Multi-paradigmatic approaches in cybersecurity economics
In cybersecurity economics, the selection of a particular methodology is a matter of interest and importance for the researchers. Methodologically sophisticated research forms an essential basis for understanding the challenges and opportunities for the richer descriptions of the behavior of cybersecurity practitioners (i.e., what they are doing and why they are doing it). This requires a broad and self-reflective approach to understand the use of a technique in socio-technical research within cybersecurity economics. Such understanding recognizes that research in this field involves more than just applying a method to create knowledge and diffuse it throughout society, organizations, and governments. This paper argues in favor of a multi-paradigmatic approach to cybersecurity economics research. Rather than adopting a single paradigm, this study suggests that results will be more prosperous and reliable if different methods from different existing paradigms are combined. Hence, it puts forward the desirability and feasibility of the multi-paradigmatic approach in cybersecurity economics research. It also outlines several practical guidelines that help design multi-paradigmatic research studies. These are illustrated with a critical evaluation of three examples of studies.
The multisided platform (MSP) is an essential business construct in the digital economy. Some of the largest companies in the world—including Google, Amazon, and eBay—exploit the MSP in their business models. Fundamental insights into the MSP are crucial to understand the business operations of the digital economy and how new innovative digital services are adopted in the market. The MSP ecosystem is complex and dynamic, and involves heterogeneous stakeholders with different business motivations. This paper classifies the various types of MSPs, distinguished by the network effect between user groups. Moreover, this paper shows how the original diffusion model of Frank Bass can be extended to analyze the temporal evolution of multisided platforms. Analytical models using coupled sets of ordinary differential equations are developed for several examples of two-sided platforms. For some of these examples, analytical solutions are found.
Kianpour, Mazaher; Kowalski, Stewart James & Øverby, Harald (2021)
Systematically Understanding Cybersecurity Economics: A Survey
Insights in the field of cybersecurity economics empower decision makers to make informed decisions that improve their evaluation and management of situations that may lead to catastrophic consequences and threaten the sustainability of digital ecosystems. By drawing on these insights, cybersecurity practitioners have been able to respond to many complex problems that have emerged within the context of cybersecurity over the last two decades. The academic field of cybersecurity economics is highly interdisciplinary since it combines core findings and tools from disciplines such as sociology, psychology, law, political science, and computer science. This study aims to develop an extensive and consistent survey based on a literature review and publicly available reports. This review contributes by aggregating the available knowledge from 28 studies, out of a collection of 628 scholarly articles, to answer five specific research questions. The focus is how identified topics have been conceptualized and studied variously. This review shows that most of the cybersecurity economics models are transitioning from unrealistic, unverifiable, or highly simplified fundamental premises toward dynamic, stochastic, and generalizable models.
Vilalta, Ricard; Munoz, Raul, Cassellas, Ramon, Martinez, Ricardo, Lopez, Victor, Dios, Oscar González de, Pastor, Antonio, Katsikas, Georgios, Klaedtke, Felix, Monti, Paolo, Mozo, Alberto, Zinner, Thomas Erich, Øverby, Harald, Gonzalez-Diaz, Sergio, Lønsethagen, Håkon, Pulido, José-Miguel & King, Daniel (2021)
TeraFlow: Secured Autonomic Traffic Management for a Tera of SDN flows
TeraFlow proposes a new type of secure, cloud-native Software Defined Networking (SDN) controller that will radically advance the state-of-the-art in beyond 5G networks by introducing novel micro-services architecture, and provide revolutionary features for both flow management (service layer) and optical/microwave network equipment integration (infras-tructure layer) by adapting new data models. TeraFlow will also incorporate security using Machine Learning (ML) and forensic evidence for multi-tenancy based on Distributed Ledgers. Finally, this new SDN controller shall be able to integrate with the current Network Function Virtualization (NFV) and Multi-access Edge Computing (MEC) frameworks as well as to other networks. The target pool of TeraFlow stakeholders expands beyond the traditional telecom operators towards edge and hyperscale cloud providers.
Kianpour, Mazaher; Kowalski, Stewart James, Øverby, Harald & Zoto, Erjon (2020)
From Cyber Incidents to Training Cognitive Situation Management: *Work in Progress
Appropriate training is an effective solution to tackle the evolving threat landscape and conflicts in the cyber domain and to fulfill security requirements. Serious games demonstrate pedagogic effectiveness in this field, however, they need to comply with national, organizational, and individual strategies and characteristics. These games provide the players, individually or in groups, with an opportunity to develop their adversarial and system thinking skills to set up effective defenses. To this end, in this paper, we propose a framework for designing serious games that raise security awareness. The proposed framework considers the complex nature of the cyber domain, the knowledge and motivation of participants, and the experiential learning using cyber ranges. The framework is based on existing frameworks, and integrates their advantages to form a comprehensive framework. Future research should refine the framework and design serious games to evaluate its effectiveness in producing desired end results.
Kianpour, Mazaher; Øverby, Harald, Kowalski, Stewart James & Frantz, Christopher (2019)
Social Preferences in Decision Making Under Cybersecurity Risks and Uncertainties
The most costly cybersecurity incidents for organizations result from the failures of their third parties. This means that organizations should not only invest in their own protection and cybersecurity measures, but also pay attention to that of their business and operational partners. While economic impact and real extent of third parties cybersecurity risks is hard to quantify, decision makers inevitably compare their decisions with other entities in their network. This paper presents a theoretically derived model to analyze the impact of social preferences and other factors on the willingness to cooperate in third party ecosystems. We hypothesize that willingness to cooperate among the organizations in the context of cybersecurity increases following the experience of cybersecurity attacks and increased perceived cybersecurity risks. The effects are mediated by perceived cybersecurity value and moderated by social preferences. These hypotheses are tested using a variance-based structural equation modeling analysis based on feedback from a sample of Norwegian organizations. Our empirical results confirm the strong positive impact of social preferences and cybersecurity attack experience on the willingness to cooperate, and support the reciprocal behavior of cybersecurity decision makers. We further show that more perception of cybersecurity risk and value deter the decision makers to cooperate with other organizations.
Li, Shuo; Wong, Eric W M, Øverby, Harald & Zukerman, Moshe (2019)
Performance Modeling of Diversity Coded Path Protection in OBS/OPS Networks
In bufferless optical burst/packet switched (OBS/OPS) networks, data (bursts or packets) may be lost due to contention or equipment failure. Diversity coding-based path protection schemes can be used to protect data from a single-trunk failure with potentially more efficient resource utilization compared to dedicated (e.g., 1 + 1) path protection schemes and help reduce the burst/packet loss ratio. This paper provides a scalable and accurate burst/packet loss ratio approximation based on the Erlang fixed-point approximation for networks that employ protection based on diversity coding and for networks that employ protection based on both diversity coding and 1 + 1 path protection. We use discrete event simulations to assess the accuracy of the approximation based on a wide range of scenarios in a 10-node circular lattice and NSFNet networks. Further, we discuss the effect of parameter settings and the effect of the choice of the wavelength selection method on the accuracy of the approximation. We consider scenarios without wavelength conversion and with full wavelength conversion and two types of users: premium and regular. The premium users, typically of mission critical services, receive protection while the regular users do not. We compare diversity coding and 1 + 1 path protection in a 10-node circular lattice network. The results show that for this example network, for the premium users and under low traffic load, the burst/packet loss ratio in OBS/OPS networks is lower for diversity coding compared to 1 + 1 path protection. However, under heavy traffic load, we observe a lower loss ratio for the case of 1 + 1 path protection.
Network effects are one of the defining properties of the digital economy. It has been shown, both in theory and practice, that network effects contribute to the growth and potential success of businesses in the digital economy. In this paper, we present a quantitative case study of network effects in Facebook for the period 2011 to 2017. We estimate the value of Facebook, and analyse how this value depends on the number of Facebook users. Our results show that there are strong network effects in Facebook, as the value per user increases more than estimations obtained from Metcalfe's law. We also outline a general theory of the strength of network effects, and quantitatively estimate the strength of network effects in Facebook.
Minimum-Storage Regenerating (MSR) codes have emerged as a viable alternative to Reed-Solomon (RS) codes as they minimize the repair bandwidth while they are still optimal in terms of reliability and storage overhead. Although several MSR constructions exist, so far they have not been practically implemented mainly due to the big number of I/O operations. In this paper, we analyze high-rate MDS codes that are simultaneously optimized in terms of storage, reliability, I/O operations, and repair-bandwidth for single and multiple failures of the systematic nodes. The codes were recently introduced in [1] without any specific name. Due to the resemblance between the hashtag sign # and the procedure of the code construction, we call them in this paper HashTag Erasure Codes (HTECs) . HTECs provide the lowest data-read and data-transfer, and thus the lowest repair time for an arbitrary sub-packetization level α , where α≤r⌈k/r⌉ , among all existing MDS codes for distributed storage including MSR codes. The repair process is linear and highly parallel. Additionally, we show that HTECs are the first high-rate MDS codes that reduce the repair bandwidth for more than one failure. Practical implementations of HTECs in Hadoop release 3.0.0-alpha2 demonstrate their great potentials.
Kralevska, Katina; Gligoroski, Danilo & Øverby, Harald (2016)
We introduce a family of balanced locally repairable
codes (BLRCs) [n, k, d] for arbitrary values of n, k and d. Similar
to other locally repairable codes (LRCs), the presented codes are
suitable for applications that require a low repair locality. The
novelty that we introduce in our construction is that we relax the
strict requirement the repair locality to be a fixed small number
I, and we allow the repair locality to be either I or I + 1. This
gives us the flexibility to construct BLRCs for arbitrary values
of n and k which partially solves the open problem of finding a
general construction of LRCs. Additionally, the relaxed locality
criteria gives us an opportunity to search for BLRCs that have
a low repair locality even when double failures occur. We use
metrics such as a storage overhead, an average repair bandwidth,
a Mean Time To Data Loss (MTTDL) and an update complexity
to compare the performance of BLRCs with existing LRCs.
Kralevska, Katina; Gligoroski, Danilo & Øverby, Harald (2016)
General Sub-Packetized Access-Optimal Regenerating Codes
We introduce a method that combines joint balanced source and network coding in optical packet-switched networks. It is an efficient way to combat packet loss that occurs due to contentions, to recover lost data due to link failures and to provide secure data transmission, i.e., secrecy. By using binary erasure codes and adding redundancy the destination is able to decode the source data when packet loss occurs. Coding at the intermediate node offers protection against single link failure. An eavesdropper cannot reconstruct the source data by eavesdropping a single link, since non-systematic coded packets are sent on disjoint paths.We also show that the proposed method has linear coding complexity, small header overhead and it does not require sending a feedback for each packet.
Panggabean, Mauritz; Rønningen, Leif Arne & Øverby, Harald (2013)
Modeling and simulating motions of human bodies in a futuristic distributed tele-immersive collaboration system for synthesizing transient input traffic
Stochastic processes have been widely employed in order to assess the network layer performance of Optical Packet Switched (OPS) networks. In this paper we consider how the Engset traffic model may be applied to evaluate the blocking probability in asynchronous bufferless OPS networks. We present two types of the Engset traffic model, i.e. the Engset lost calls cleared traffic model and the Engset overflow traffic model. For both traffic models, the time-, call-, and traffic congestion are derived. A numerical study shows that the observed blocking probability is dependent on the choice of traffic model and performance metric.
Øverby, Harald & Stol, Norvald (2005)
Providing absolute QoS in asynchronous bufferless optical packet/burst switched networks with the adaptive preemptive drop policy
28
Øverby, Harald & Stol, Norvald (2004)
Effects of the switching time in OPS/OBS networks
2(3) , s. 131- 134.
In this paper we present an analytical model, which considers the effects of the switching time on the network performance in service differentiated Optical Packet/Burst Switched networks (OPS/OBS). Our results indicate that the switching time must be less than 10 % of the packet/burst duration in order to avoid any significant reductions in the network performance. Furthermore, regarding a network with full wavelength conversion, we show that the benefits of statistical resource sharing are almost non-existent for low priority traffic when the switching time is large.
Nord, Martin; Øverby, Harald & Stol, Norvald (2004)
Packet Loss Rate- and Jitter Differentiating QoS Schemes for Asynchronous Optical Packet Switches
3(12) , s. 866- 866.
Arnemo, Jon Martin; Heim, Morten, Øen, Egil Ole, Berntsen, Finn, Kvale, Bjarne, Os, Øystein & Øverby, Harald (2004)
Dødelighet ved medikamentell immobilisering av elg i Norge 1976-2004 CHEMICAL IMMOBILIZATION OF FREE-RANGING MOOSE IN NORWAY 1976-2004
116(7) , s. 531- 535.
I perioden 1976-2000 ble det utført i alt 1898 medikamentelle immobiliseringer av viltlevende elg i Norge. Tretten dyr(0,7 ? døde eller måtte avlives i tilslutning til innfangingen. Anbefalt metode for immobilisering av viltlevende elg i Norge er administrasjon av etorfin ved hjelp av injeksjonsvåpenfra helikopter på snødekt mark. Risikoen for mortalitet ved denne metoden er meget liten: kun åtte dyr (0,5 ? døde av i alt 1526 immobiliseringer foretatt fra 1984 til 2004. Dødsårsaker var drukning (én voksen ku og én voksen okse), respirasjonsstans etter intravaskulær injeksjon (én voksen ku), skade iryggmargen forårsaket av injeksjonspilen (én avmagret kalv med beinskjørhet og parasittær lungebetennelse) og respirasjonsstans forårsaket av en relativ overdosering (fire kalver i dårlig kondisjon). Standard dose for etorfin er 7,50 ? 9,00mg/voksen og 3,75 ?4,50 mg/kalv. Dyr som ikke har lagt seg innenti minutter etter første injeksjon, kan påskytes på nyttmed full dose. A total of 1,898 chemical immobilizations of free-rangingmoose (Alces alces) were carried out in Norway from 1976 to 2004. Thirteen animals (0.7 ? died or were euthanized. The recommended method for immobilization of free-ranging moose inNorway is darting from a helicopter with etorphine on snow-covered ground. The risk of mortality with this method is verylow, only eight animals (0.5 ? died during 1,526 captures from 1984 to 2004. Causes of mortality were drowning in one adult female and one adult male, respiratory arrest due to intravascular injection in an adult female, traumatic spinal lesions due to dart impact in the lumbar region in a cachectic calf with osteoporosis and verminous pneumonia, and respiratoryarrest due to relative overdosing in four calves in poor body condition. The standard doses of etorphine are 7.5-9.0 mg/animal in adults and 3.75-4.50 mg/animal in calves. Animals which are not down within ten minutes after initial darting canbe redarted with a full dose.
Øverby, Harald & Stol, Norvald (2004)
Effects of bursty traffic in service differentiated Optical Packet Switched networks
Service differentiation is a crucial issue in the next-generation Optical Packet Switched networks. In this paper we examine how bursty traffic influences the performance of a service differentiated Optical Packet Switched network. By using time-continuous Markov chains, we derive explicit results for the packet loss rates in the case of a bursty hyper-exponential arrival process. Results indicate that the performance is degraded as the burstiness of the arrival process increases.
Øverby, Harald & Stol, Norvald (2004)
Quality of Service in Asynchronous Bufferless Optical Packet Switched Networks
27(2-4) , s. 151- 179.
Optical Packet Switching (OPS) is a promising technology for future core networks due to the ability to handle bursty traffic, adaptability to changes in the network infrastructure and good network utilization. In order to provide sufficient Quality of Service (QoS) to the emerging range of real-time and critical business applications, service differentiation should be present in future OPS. This paper presents the Preemptive Drop Policy (PDP), which provides service differentiation in asynchronous bufferless OPS. Based on time-continuous Markov chains, we introduce an analytical model of the PDP for switches with and without wavelength conversion. We extend the PDP into the Adaptive PDP (APDP), which provides absolute QoS guarantees in OPS. Simulations performed validate our analytical model and show that the APDP operates properly in a dynamic changing system load scenario.
Øverby, Harald (2004)
Network layer packet redundancy in optical packet switched networks
A crucial issue in optical packet switched (OPS) networks is packet losses at the network layer caused by contentions. This paper presents the network layer packet redundancy scheme (NLPRS), which is a novel approach to reduce the end-to-end data packet loss rate in OPS networks. By introducing redundancy packets in the OPS network, the NLPRS enables a possible reconstruction of data packets that are lost due to contentions. An analytical model of the NLPRS based on reduced load Erlang fix-point analysis is presented. Simulations of an OPS ring network show that the NLPRS is in particular efficient in small networks operating at low system loads. Results also show how the arrival process, packet length distribution, network size and redundancy packet scheduling mechanism influence the NLPRS performance.
Øien, Geir Egil; Breivik, Morten, Hergum, Ragnar, Ildstad, Erling, Jaccheri, Maria Letizia, Rønquist, Einar & Øverby, Harald (2016)
Teknisk kybernetikk og elkraftteknikk må organiseres sammen med resten av NTNUs IKT- og elektrofag
[Kronikk]
Øverby, Harald & Audestad, Jan Arild (2021)
Introduction to Digital Economics: Foundations, Business Models and Case Studies
[Textbook].
Kianpour, Mazaher; Kowalski, Stewart James, Øverby, Harald & Zoto, Erjon (2020)
From Cyber Incidents to Training Cognitive Situation Management
[Conference Poster]. Event
Øverby, Harald & Audestad, Jan Arild (2018)
Digital Economics
[Textbook].
Øverby, Harald (2018)
Network Effects in Facebook
[Conference Lecture]. Event
Kralevska, Katina; Gligoroski, Danilo & Øverby, Harald (2016)
Performance Analysis of Regenerating Codes
[Conference Poster]. Event
Idland, Elisabeth; Øverby, Harald & Arild, audestad Jan (2015)
Economic Markets for Video Streaming Services: A Case Study of NetFlix and Popcorn Time
[Conference Lecture]. Event
Yang, Shuna; Stol, Norvald & Øverby, Harald (2013)
a novel approach in modeling multi-service optical packet switched networks with the preemptive drop policy
[Conference Lecture]. Event
Savi, Michele; Stol, Norvald, Øverby, Harald & Raffaelli, Carla (2012)
Loss, Complexity and Cost Analysis of an Optical Switching Fabric Using Fixed Converters
[Conference Lecture]. Event
Øverby, Harald; Biczok, Gergely & Audestad, Jan Arild (2012)
Modeling Dynamic ICT Services Markets
[Conference Lecture]. Event
Savi, Michele; Stol, Norvald, Øverby, Harald & Raffaelli, Carla (2012)
Contention Resolution Using Parametric Wavelength Converters: Performance and Cost Analysis
[Conference Lecture]. Event
Yang, Shuna; Stol, Norvald & Øverby, Harald (2012)
Performance Modeling of Asynchronous Bufferless Optical Packet Switches with Limited Range Wavelength Converters
[Conference Lecture]. Event
Øverby, Harald (2012)
Cost Comparison of 1+1 Path Protection Schemes: A Case for Coding
[Conference Lecture]. Event
Biczok, Gergely & Øverby, Harald (2011)
Combating Packet Loss in OPS networks: A Case for Network Coding
[Conference Lecture]. Event
Øverby, Harald (2011)
Interconnecting Two Intra-Domain Wavelength Routed Optical Networks Using an Optical Packet Switch
[Conference Lecture]. Event
Øverby, Harald (2009)
Reduced load Engset fix point analysis for optical burst switched networks
[Conference Lecture]. Event
Øverby, Harald (2009)
Analysis of a bufferless OpMiGua Node
[Conference Lecture]. Event
Øverby, Harald (2009)
Packet Loss Differentiation using Network Layer Packet Redundancy in Optical Packet/Burst Switched Networks
[Conference Lecture]. Event
Kimsas, Andreas; Bjørnstad, Steinar, Øverby, Harald & Stol, Norvald (2007)
Dependability differentiation in Optical Packet Switched Networks
[Conference Lecture]. Event
Øverby, Harald & Stol, Norvald (2004)
Providing QoS in OPS/OBS networks with the Preemptive Drop Policy
[Conference Lecture]. Event
Øverby, Harald (2004)
QoS in slotted bufferless optical packet switched networks
[Conference Lecture]. Event
Undheim, Astrid; Øverby, Harald & Stol, Norvald (2004)
Absolute QoS in Synchronous Optical Packet Switched Networks
[Conference Lecture]. Event
Øverby, Harald & Stol, Norvald (2004)
Evaluating and Comparing Two Different Service Differentiation Methods for OPS: The Wavelength Allocation algorithm and The Preemptive Drop Policy
[Conference Lecture]. Event
Moseng, Tor K.; Øverby, Harald & Stol, Norvald (2004)
Merit Based Scheduling in Asynchronous Bufferless Optical Packet Switched Networks
[Conference Lecture]. Event
Øverby, Harald (2004)
Optical Packet Switched Metro Networks
[Conference Lecture]. Event
Øverby, Harald (2004)
Performance modelling of synchronous bufferless OPS networks
[Conference Lecture]. Event
Øverby, Harald & Stol, Norvald (2004)
Exploiting network layer packet redundancy to reduce the end-to-end data packet loss rate in optical packet/burst switched networks
[Conference Lecture]. Event
Øverby, Harald & Stol, Norvald (2003)
A Teletraffic Model of Service Differentiation with Electronic Buffering in Optical Packet Switched Networks
[Conference Lecture]. Event
We present a teletraffic model of service differentiation in Optical Packet Switched networks. Electronic buffering is applied in order to reduce packet loss rate for low priority traffic. Analytical expressions and simulation results are reported.
Øverby, Harald (2003)
A Study on Service Differentiation in Bufferless Optical Packet/Burst Switched Networks
[Conference Lecture]. Event
Øverby, Harald & Stol, Norvald (2003)
A Teletraffic Model for Service Differentiation in OPS Networks
[Conference Lecture]. Event
This paper presents a formal teletraffic model for service differentiation in optical packet switched networks by utilizing the wavelength domain. Expressions for the time congestion are derived. Simulation results are also reported.
Øverby, Harald (2003)
An adaptive service differentiation algorithm for optical packet switched networks
[Conference Lecture]. Event
This paper presents a novel adaptive service differentiation algorithm for Optical Packet Switched (OPS) networks. Previous research has aimed at presenting algorithms that achieves service differentiation in OPS networks by utilizing the wavelength domain. However, simulations show that these algorithms result inn fluctuating packet loss rate as the system load is varied. The adaptive algorithm proposed here measures the packet loss rate for high priority traffic over a time interval and adjusts the number of wavelength converters reserved for high priority traffic accordingly in order to achieve a constant packet loss rate. However, due to the self-similarity of the Internet traffic, special considerations must be taken into account in order to avoid oscillations in the number of wavelength converters reserved for high priority traffic.
