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  • 1.
    Abrahamsson, Henrik
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Traffic measurement and analysis1999Report (Other academic)
    Abstract [en]

    Measurement and analysis of real traffic is important to gain knowledge about the characteristics of the traffic. Without measurement, it is impossible to build realistic traffic models. It is recent that data traffic was found to have self-similar properties. In this thesis work traffic captured on the network at SICS and on the Supernet, is shown to have this fractal-like behaviour. The traffic is also examined with respect to which protocols and packet sizes are present and in what proportions. In the SICS trace most packets are small, TCP is shown to be the predominant transport protocol and NNTP the most common application. In contrast to this, large UDP packets sent between not well-known ports dominates the Supernet traffic. Finally, characteristics of the client side of the WWW traffic are examined more closely. In order to extract useful information from the packet trace, web browsers use of TCP and HTTP is investigated including new features in HTTP/1.1 such as persistent connections and pipelining. Empirical probability distributions are derived describing session lengths, time between user clicks and the amount of data transferred due to a single user click. These probability distributions make up a simple model of WWW-sessions.

  • 2.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Temporal Characteristics of Large IP Traffic Flows2003Report (Other academic)
    Abstract [en]

    Several studies of Internet traffic have shown that it is a small percentage of the flows that dominate the traffic. This is often referred to as the mice and elephants phenomenon. It has been proposed that this might be one of very few invariants of Internet traffic and that this property could somehow be used for traffic engineering purposes. The idea being that one in a scalable way could control a major part of the traffic by only keeping track of a small number of flows. But for this the large flows must also be stable in the meaning that they should be among the largest flows during long periods of time. In this work we analyse packet traces of Internet traffic and study the temporal characteristics of large aggregated traffic flows defined by destination address prefixes.

  • 3.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Using empirical distributions to characterize web client traffic and to generate synthetic traffic2000Conference paper (Refereed)
  • 4.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A Multi Path Routing Algorithm for IP Networks Based on Flow Optimisation.2002Conference paper (Refereed)
  • 5.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    From QoS provisioning to QoS charging2002In: Proceedings of the Second International Workshop on Internet Charging and QoS Technologies, ICQT 2002, 2002, 1, Vol. Lectures Notes in Computer Science (LNCS) no. 2511, p. 135-144Conference paper (Refereed)
  • 6.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Tholin, Per
    Delay and Traffic Intensity Monitoring in an Operational IP Network2015Conference paper (Refereed)
  • 7.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Caching for IPTV distribution with time-shift2013Conference paper (Refereed)
  • 8.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Robust Traffic Engineering using L-balanced Weight-Settings in OSPF/IS-IS2009Conference paper (Refereed)
  • 9.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Simulation of IPTV caching strategies2010Conference paper (Refereed)
    Abstract [en]

    IPTV, where television is distributed over the Internet Protocol in a single operator network, has become popular and widespread. Many telecom and broadband companies have become TV providers and distribute TV channels using multicast over their backbone networks. IPTV also means an evolution to time-shifted television where viewers now often can choose to watch the programs at any time. However, distributing individual TV streams to each viewer requires a lot of bandwidth and is a big challenge for TV operators. In this paper we present an empirical IPTV workload model, simulate IPTV distribution with time-shift, and show that local caching can limit the bandwidth requirements significantly.

  • 10.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Gunnar, Anders
    RISE, Swedish ICT, SICS.
    Traffic engineering in ambient networks: challenges and approaches2004In: Swedish National Computer Networking Workshop, 2004, 1Conference paper (Refereed)
    Abstract [en]

    The focus of this paper is on traffic engineering in ambient networks. We describe and categorize different alternatives for making the routing more adaptive to the current traffic situation and discuss the challenges that ambient networks pose on traffic engineering methods. One of the main objectives of traffic engineering is to avoid congestion by controlling and optimising the routing function, or in short, to put the traffic where the capacity is. The main challenge for traffic engineering in ambient networks is to cope with the dynamics of both topology and traffic demands. Mechanisms are needed that can handle traffic load dynamics in scenarios with sudden changes in traffic demand and dynamically distribute traffic to benefit from available resources. Trade-offs between optimality, stability and signaling overhead that are important for traffic engineering methods in the fixed Internet becomes even more critical in a dynamic ambient environment.

  • 11.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Hagsand, Olof
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    TCP over High Speed Variable Capacity Links: A Simulation Study for Bandwidth Allocation2002Conference paper (Refereed)
  • 12.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A case for resource management in IPTV distribution2008Conference paper (Refereed)
  • 13.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Resource Management for IPTV distribution2009In: ERCIM News, Vol. 77Article in journal (Other academic)
  • 14.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    DTMsim - DTM channel simulation in ns2001Report (Other academic)
    Abstract [en]

    Dynamic Transfer Mode (DTM) is a ring based MAN technology that provides a channel abstraction with a dynamically adjustable capacity. TCP is a reliable end to end transport protocol capable of adjusting its rate. The primary goal of this work is investigate the coupling of dynamically allocating bandwidth to TCP flows with the affect this has on the congestion control mechanism of TCP. In particular we wanted to find scenerios where this scheme does not work, where either all the link capacity is allocated to TCP or congestion collapse occurs and no capacity is allocated to TCP. We have created a simulation environment using ns-2 to investigate TCP over networks which have a variable capacity link. We begin with a single TCP Tahoe flow over a fixed bandwidth link and progressively add more complexity to understand the behaviour of dynamically adjusting link capacity to TCP and vice versa.

  • 15.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Nordmark, Mattias
    Program Popularity and Viewer Behaviour in a Large TV-on-Demand System2012Conference paper (Refereed)
  • 16.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A host interface to the DTM high speed network1992Conference paper (Refereed)
  • 17.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A performance model for integrated layer processing1997Conference paper (Refereed)
    Abstract [en]

    Integrated Layer Processing is an implementation technique for data manipulation functions in communication protocols. The purpose of this technique is to increase communication performance. It reduces the number of memory accesses and thus relieves the memory bandwidth bottleneck. Integrated Layer Processing can however, in some situations, substantially increase the number of memory accesses, and therefore instead reduce performance. The main reason is contention for processor registers. We present a performance model that captures the memory behavior of data manipulation functions for both integrated and sequential implementations. By comparing the model to measurements of real and synthetic data manipulation functions, we show that the model accurately predicts the performance. The model can be used to assess whether an integrated implementation will perform better or worse than a sequential implementation. The situations where integration would reduce performance can then be avoided without spending a lot of effort on a more complex integrated implementation.

  • 18.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Improving computer communication performance by reducing memory bandwidth consumption1997Doctoral thesis, monograph (Other academic)
  • 19.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    NetInf Routing Using Hints2013Conference paper (Refereed)
    Abstract [en]

    We define a global routing mechanism for the NetInf protocol, part of the NetInf information-centric networking architecture. The mechanism makes use of two levels of aggregation in order to provide the scalability needed for a global network. An anticipated $10^{15}$ number of individual named data objects are aggregated to in the order of 500K routing hints which are very feasible to handle with existing routing technology. The hints are then used to forward requests for named data towards the publisher.

  • 20.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Andersson, Anders
    Hagsand, Olof
    RISE - Research Institutes of Sweden, ICT, SICS.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dimensioning links for IP telephony2001In: Proceedings of the 2nd IP-Telephony Workshop (IPtel 2001), 2-3 April 2001, New York City, New York, USA, 2001, 1Conference paper (Refereed)
    Abstract [en]

    Packet loss is an important parameter for dimensioning network links or traffic classes carrying IP telephony traffic. We present a model based on the Markov modulated Poisson process (MMPP) which calculates packet loss probabilities for a set of super positioned voice input sources and the specified link properties. We do not introduce another new model to the community, rather try and verify one of the existing models via extensive simulation and a real world implementation. A plethora of excellent research on queuing theory is still in the domain of ATM researchers and we attempt to highlight its validity to the IP Telephony community. Packet level simulations show very good correspondence with the predictions of the model. Our main contribution is the verification of the MMPP model with measurements in a laboratory environment. The loss rates predicted by the model are in general close to the measured loss rates and the loss rates obtained with simulation. The general conclusion is that the MMPP-based model is a tool well suited for dimensioning links carrying packetized voice in a system with limited buffer space.

  • 21.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Hagsand, Olof
    RISE - Research Institutes of Sweden, ICT, SICS.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dimensioning Links for IP Telephony2000Report (Other academic)
    Abstract [en]

    Transmitting telephone calls over the Internet causes problems not present in current telephone technology such as packet loss and delay due to queueing in routers. In this undergraduate thesis we study how a Markov modulated Poisson process is applied as an arrival process to a multiplexer and we study the performance in terms of loss probability. The input consists of the superposition of independent voice sources. The predictions of the model is compared with results obtained with simulations of the multiplexer made with a network simulator. The buffer occupancy distribution is also studied and we see how this distribution changes as the load increases.

  • 22.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Aranda, Pedro A.
    Chemouil, Prosper
    Correia, Luis M.
    Holger, Karl
    Oueslati, Sara
    Söllner, Michael
    Welin, Annikki
    Content, Connectivity and Cloud: Ingredients for the Network of the Future2011In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 49, p. 62-70Article in journal (Refereed)
    Abstract [en]

    A new network architecture for the Internet needs ingredients from three approaches: information-centric networking, cloud computing integrated with networking, and open connectivity. Information-centric networking considers pieces of information as first-class entities of a networking architecture, rather than only indirectly identifying and manipulating them via a node hosting that information; this way, information becomes independent from the devices they are stored in, enabling efficient and application-independent information caching in the network. Cloud networking offers a combination and integration of cloud computing and virtual networking. It is a solution that distributes the benefits of cloud computing more deeply into the network, and provides a tighter integration of virtualisation features at computing and networking levels. To support these concepts, open connectivity services need to provide advanced transport and networking mechanisms, making use of network and path diversity (even leveraging direct optical paths) and encoding techniques, and dealing with ubiquitous mobility of user, content and information objects in a unified way.

  • 23.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Multimedia transport service and protocol issues1992Report (Other academic)
    Abstract [en]

    This paper considers the issues of a real time transport service needed by multimedia applications for transferring digital video and audio. Three classes of transport service are defined with different levels of real time constraints. Methods for error control are considered for the classes, and the classes are discussed with respect to the application requirements.

  • 24.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    Integrated layer processing can be hazardous to your performance1997Conference paper (Refereed)
    Abstract [en]

    Integrated Layer Processing (ILP) has been presented as an implementation technique to improve communication protocol performance by reducing the number of memory references. Previous research has however not pointed out that in some circumstances ILP can significantly increase the number of memory references, resulting in lower communication throughput. We explore the performance effects of applying ILP to data manipulation functions with varying characteristics. The functions are generated from a set of parameters including input and output block size, state size and number of instructions. We present experimental data for varying function state sizes, number of integrated functions and instruction counts. The results clearly show that the aggregated state of the functions must fit in registers for ILP to be competitive.

  • 25.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    The applicability of integrated layer processing1998In: IEEE Journal on Selected Areas in Communications, Vol. 16, no 3, p. 317-331Article in journal (Refereed)
    Abstract [en]

    In this paper we review previous work on the applicability and performance of Integrated Layer Processing (ILP). ILP has been shown to clearly improve computer communication performance when integrating simple data manipulation functions, but the situation has been less clear for more complex functions and complete systems. We discuss complications when applying ILP to protocol stacks, the requirements of ILP on the communication subsystem, caching aspects, the importance of the processor registers, and a model for predicting the performance of data manipulation functions. We conclude that the main drawback of ILP is its limited aplicability to complex data manipulation functions. The performance to expect from an ILP implementation also depends heavily on the protocol architecture and the host system architecture.

  • 26.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Towards predictable ILP performance-controlling communication buffer cache effects1995Conference paper (Refereed)
  • 27.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    Towards predictable ILP performance-controlling communication buffer cache effects1996In: The Australian Computer Journal, Vol. 28, p. 66-71Article in journal (Refereed)
    Abstract [en]

    Cache memory behavior is becoming more and more important as the speed of CPUs is increasing faster than the speed of memories. The operation of caches are statistical which means that the system level performance becomes unpredictable. In this paper we investigate the worst case behavior of cache line conflicts in the context of communication protocols implemented using Integrated Layer Processing. The goal of our work is to control the cache by placing communication buffers and code in non-conflicting positions in the cache. The result would be higher and more predictable performance. Our first results indicate that the worst case behavior can be up to almost four times slower than the best case.

  • 28.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Moldeklev, Kjersti
    The performance of a no-copy API for communication1995Conference paper (Refereed)
    Abstract [en]

    We present a so-called no-copy Application Programming Interface (API) for communication. The interface avoids copying when data is transferred between the application and operating system kernel address spaces. The API is an extension to the socket interface for SunOS, and has been implemented on Sun SPARCstations equipped with Fore Systems ATM adapters. Throughput for the no-copy API is 85 Mbit/s for 8K UDP messages, to be compared to 57 Mbit/s for the regular API on the SPARCstation 2. Processing times through the TCP and UDP stacks are reduced by up to 30% for the SPARCstation 2 and by more than 50% for the SPARCstation 10.

  • 29.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Brunner, Marcus
    Eggert, Lars
    Hancock, Robert
    Schmid, Stefan
    Invariants: A New Design Methodology for Network Architectures2004Conference paper (Refereed)
    Abstract [en]

    The first age of Internet architectural thinking concentrated on defining the correct principles for designing a packet-switched network and its application protocol suites. Although these same principles remain valid today, they do not address the question of how to reason about the evolution of the Internet or its interworking with other networks of very different heritages. This paper proposes a complementary methodology, motivated by the view that evolution and interworking flexibility are determined not so much by the principles applied during initial design, but by the choice of fundamental components or "design invariants" in terms of which the design is expressed. The paper discusses the characteristics of such invariants, including examples from the Internet and other networks, and considers what attributes of invariants best support architectural flexibility.

  • 30.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    D’Ambrosio, Matteo
    4WARD.
    Dannewitz, Christian
    4WARD.
    Marchisio, Marco
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ohlman, Börje
    Pentikousis, Kostas
    Rembarz, René
    Strandberg, Ove
    Vercellone, Vinicio
    Design considerations for a network of information2008Conference paper (Refereed)
    Abstract [en]

    The existing Internet ecosystem is a result of decades of evolution. It has managed to scale well beyond the original aspirations. Evolution, though, highlighted a certain degree of inadequacies that is well documented. In this position paper we present the design considerations for a re-architected global networking architecture which delivers dissemination and non-dissemination objects only to consenting recipients, reducing unwanted traffic, linking information producers with consumers independently of the hosts involved, and connects the digital with the physical world. We consider issues ranging from the proposed object identifier/locator split to security and trust as we transition towards a Network of Information and relate our work with the emerging paradigm of publish/subscribe architectures. We introduce the fundamental components of a Network of Information, i.e., name resolution, routing, storage, and search, and close this paper with a discussion about future work.

  • 31.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Dannewitz, Christian
    SAIL.
    Imbrenda, Claudio
    Kutscher, Dirk
    Ohlman, Börje
    A Survey of Information-Centric Networking2012In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 50, p. 26-36Article in journal (Refereed)
    Abstract [en]

    The information-centric networking (ICN) concept is a significant common approach of several Future Internet research activities. The approach leverages in-network caching, multi-party communication through replication, and interaction models decoupling senders and receivers. The goal is to provide a network infrastructure service that is better suited to today's use, in particular content distribution and mobility, and that is more resilient to disruptions and failures. The ICN approach is being explored by a number of research projects. We compare and discuss design choices and features of proposed ICN architectures, focussing on the following main components: named data objects, naming and security, API, routing and transport, and caching. We also discuss the advantages of the ICN approach in general.

  • 32.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Dannewitz, Christian
    Imbrenda, Claudio
    Kutscher, Dirk
    Ohlman, Börje
    A Survey of Information-Centric Networking (Draft)2011Conference paper (Refereed)
  • 33.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Eggert, Lars
    Ohlman, Börje
    Rajahalme, Jarno
    Schieder, Andreas
    Names, addresses and identities in ambient networks2005Conference paper (Refereed)
    Abstract [en]

    Ambient Networks interconnect independent realms that may use different local network technologies and may belong to different administrative or legal entities. At the core of these advanced internetworking concepts is a flexible naming architecture based on dynamic indirections between names, addresses and identities. This paper gives an overview of the connectivity abstractions of Ambient Networks and then describes its naming architecture in detail, comparing and contrasting them to other related next-generation network architectures.

  • 34.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Eggert, Lars
    Ohlman, Börje
    Schieder, Andreas
    Ambient networks: Bridging heterogeneous network domains2005Conference paper (Refereed)
    Abstract [en]

    Providing end-to-end communication in heterogeneous internetworking environments is a challenge. Two fundamental problems are bridging between different internetworking technologies and hiding of network complexity and differences from both applications and application developers. This paper presents abstraction and naming mechanisms that address these challenges in the Ambient Networks project. Connectivity abstractions hide the differences of heterogeneous internetworking technologies and enable applications to operate across them. A common naming framework enables end-to-end communication across otherwise independent internetworks and supports advanced networking capabilities, such as indirection or delegation, through dynamic bindings between named entities.

  • 35.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Gunningberg, Per
    A minimal-copy network interface architecture supporting ILP and ALF1994Conference paper (Refereed)
  • 36.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Moldeklev, Kjersti
    Increasing communication performance with a minimal-copy data path supporting ILP and ALF1996In: Journal of High Speed Networks, Vol. 5, no 2, p. 203-214Article in journal (Refereed)
    Abstract [en]

    Many current implementations of communication subsystems on workstation class computers transfer communication data to and from primary memory several times. This is due to software copying between user and operating system address spaces, presentation layer data conversion and other data manipulation functions. The consequence is that memory bandwidth is one of the major performance bottlenecks limiting high speed communication on these systems. We propose a communication subsystem architecture with a minimal-copy data path to widen this bottleneck. The architecture is tailored for protocol implementations using Integrated Layer Processing (ILP) and Application Layer Framing (ALF). We choose to implement these protocols in the address space of the application program. We present a new application program interface (API) between the protocols and the communication service in the operating system kernel. The API does not copy data, but instead passes pointers to page size data buffers. We analyze and discuss ILP loop and cache memory requirements on these buffers. Initial experiments show that the API can increase the communication performance with 50% compared to a standard BSD Unix socket interface.

  • 37.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Hidell, Markus
    Ngai, Edith
    Internet of Things for Smart Cities: Interoperability and Open Data2016In: IEEE Internet Computing, ISSN 1089-7801, E-ISSN 1941-0131, p. 52-56Article in journal (Refereed)
    Abstract [en]

    The Internet of Things (IoT) for smart cities needs accessible open data and open systems, so that industries and citizens can develop new services and applications. As an example, the authors provide a case study of the GreenIoT platform in Uppsala, Sweden.

  • 38.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Hurtig, Per
    Abrahamsson, Henrik
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Grinnemo, Karl-Johan
    Brunstrom, Anna
    Are MIRCC and Rate-based Congestion Control in ICN READY for Variable Link Capacity?2017Conference paper (Refereed)
    Abstract [en]

    Information-centric networking~(ICN) has been introduced as a potential future networking architecture. ICN promises an architecture that makes information independent from location, application, storage, and transportation. Still, it is not without challenges. Notably, there are several outstanding issues regarding congestion control: Since ICN is more or less oblivious to the location of information, it opens up for a single application flow to have several sources, something which blurs the notion of transport flows, and makes it very difficult to employ traditional end-to-end congestion control schemes in these networks. Instead, ICN networks often make use of hop-by-hop congestion control schemes. However, these schemes are also tainted with problems, e.g., several of the proposed ICN congestion controls assume fixed link capacities that are known beforehand. Since this seldom is the case, this paper evaluates the consequences in terms of latency, throughput, and link usage, variable link capacities have on a hop-by-hop congestion control scheme, such as the one employed by the Multipath-aware ICN Rate-based Congestion Control~(MIRCC). The evaluation was carried out in the OMNeT++ simulator, and demonstrates how seemingly small variations in link capacity significantly deteriorate both latency and throughput, and often result in inefficient network link usage.

  • 39.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Jonasson, Arndt
    RISE, Swedish ICT, SICS, Software and Systems Engineering Laboratory.
    Scalable Live TV Distribution with NetInf to Android Devices (poster/demo)2014Conference paper (Refereed)
  • 40.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Jonasson, Arndt
    RISE, Swedish ICT, SICS, Software and Systems Engineering Laboratory.
    Ohlman, Börje
    HTTP Live Streaming over NetInf Transport2014Conference paper (Refereed)
  • 41.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Karl, Holger
    Kutscher, Dirk
    Zhang, Lixia
    Special section on Information-Centric Networking (editorial)2013In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 36Article in journal (Refereed)
  • 42.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Lindgren, Anders
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Wu, Yanqiu
    Demo: Experimental Feasibility Study of CCN-lite on Contiki Motes for IoT Data Streams2016In: ICN 2016: 3rd ACM Conference on Information-Centric Networking, 2016Conference paper (Refereed)
  • 43.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Lindgren, Per
    Sirotkin, Teet
    SPION: Secure Protocols in OSI Networks1989Report (Other academic)
    Abstract [en]

    SPION: Secure Protocols in OSI Networks This report describes how security services can be realized in a computer network using the protocols of the Open Systems Interconnection (OSI) reference model for communication. The report starts with defining security requirements for a "typical" local area network in a company, university or similar organization. It is assumed that the organization does not use the network for transfer of extremely sensitive information, such as military secrets. A set of security services, as specified in the OSI security architecture, are selected in order to satisfy the requirements. The selected services are then placed in suitable layers of the OSI model according to the criteria in the security architecture, and to the taste of the authors. The report concentrates on the transport layer. An extension of the OSI transport protocol, class 4, including security services is described in detail. The protocol is a fully compatible extension of the standard transport protocol. Key management is another topic which is included in the report. A key management system for handling public keys and digital signatures based on an article by Dorothy E. Denning is described. The system includes functions for distributing and validating public keys, and registering and later verifying digital signatures. A key management protocol supporting these functions is defined for communication between ordinary open systems and special key server systems.

  • 44.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Lindgren, Per
    Sirotkin, Teet
    State of the art in network security1990Report (Other academic)
    Abstract [en]

    This report is an effort to describe the state-of-the-art in computer network security focusing on the OSI Security architecture. Other sources of information include the NCSC "Trusted Network Interpretation of the TCSEC". The report describes the security threats imposed on networks and the countermeasures available. It gives a detailed description of the security services defined in the OSI Security architecture and the mechanisms proposed for realizing these services. An overview of security management with emphasis on key management is also included. The report contains numerous references to books and articles in the field of network security.

  • 45.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ohlman, Börje
    Axelsson, Erik
    Brown, Lars
    Experiments with Subversion Over OpenNetInf and CCNx2011Conference paper (Refereed)
    Abstract [en]

    We describe experiences and insights from adapting the Subversion version control system to use the network service of two information-centric networking (ICN) prototypes: OpenNetInf and CCNx. The evaluation is done using a local collaboration scenario, common in our own project work where a group of people meet and share documents through a Subversion repository. The measurements show a performance benefit already with two clients in some of the studied scenarios, despite being done on un-optimised research prototypes. The conclusion is that ICN clearly is beneficial also for non mass-distribution applications.

  • 46.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ohlman, Börje
    Axelsson, Erik
    Brown, Lars
    Subversion Over OpenNetInf and CCNx2011Conference paper (Refereed)
    Abstract [en]

    We describe experiences and insights from adapting the Subversion version control system to use the network service of two information-centric networking (ICN) prototypes: OpenNetInf and CCNx. The evaluation is done using a local collaboration scenario, common in our own project work where a group of people meet and share documents through a Subversion repository. The measurements show a performance benefit already with two clients in some of the studied scenarios, despite being done on un-optimised research prototypes. The conclusion is that ICN clearly is beneficial also for non mass-distribution applications. It was straightforward to adapt Subversion to fetch updated files from the repository using the ICN network service. The adaptation however neglected access control which will need a different approach in ICN than an authenticated SSL tunnel. Another insight from the experiments is that care needs to be taken when implementing the heavy ICN hash and signature calculations. In the prototypes, these are done serially, but we see an opportunity for parallelisation, making use of current multi-core processors.

  • 47.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ohlman, Börje
    Malik, Adeel Mohammad
    NetInf Live Video Specification2015Other (Other academic)
    Abstract [en]

    This document specifies how the NetInf information-centric network service can be used for transport of live video streaming. To illustrate this it describes a prototype system that was developed to be used at "events with large crowds", e.g., sports events. The specification defines how the used video format is mapped to NetInf named data objects (NDOs). It also describe how NetInf messages are used to transfer the NDOs.

  • 48.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Pink, Stephen
    RISE, Swedish ICT, SICS.
    Gunningberg, Per
    RISE, Swedish ICT, SICS.
    A Host Interface to the DTM Network1992Report (Other academic)
    Abstract [en]

    DTM, dynamic synchronous transfer mode, is a new time division multiplexing technique for fiber networks currently being developed and implemented at the Royal Institute of Technology in Stockholm, Sweden. This paper describes the hardware and software aspects of the design of an SBus host interface to the DTM network for a Sun SPARCstation. The interface is based on a dual port memory residing on the interface card and accesible over the SBus from the host CPU. The host operating system allocates message buffers directly in this memory. The interface has hardware support for segmenting and reassembling packets to and from the data units of the DTM. The software part of the interface manages the shared memory and the virtual circuits provided by the DTM network.

  • 49.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Vercellone, Vinicio
    Networking of Information – An information-centric approach to the network of the future2010Conference paper (Refereed)
  • 50. Almberg, Wah-Sui
    et al.
    Boman, Magnus
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    An active agent portfolio algorithm2003In: Artificial intelligence and computer science, Nova publishers , 2003, 1, p. 123-134Chapter in book (Refereed)
    Abstract [en]

    An algorithm for managing a portfolio of stocks using a trading agent is presented. A simulation game inspired by history-based Parrondo games is described. A performance measure is defined, with which various strategy mixes can be judged. Even when transaction costs are taken into account, active portfolio management (as opposed to Buy and Hold) is shown to be profitable.

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