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Klein, D., Zinner, T., Borchert, K., Lange, S., Singeorzan, V., Schmid, M.: Evaluation of Video Quality Monitoring based on Pre-computed Frame Distortions. 19th EUNICE Workshop on Advances in Communication Networking, Best Paper Award. , Chemnitz, Germany (2013).
A large fraction of the current Internet traffic is caused by video streaming. Due to the growing expectations of video consumers, monitoring video applications is getting more and more important for network and service providers. In a previous work, we proposed a video quality monitoring solution which utilizes the full reference SSIM metric to improve the monitoring in the network by distributing pre-computed distortion information induced by frame losses. To improve scalability, we introduced a less complex algorithm which infers the distortion for higher loss scenarios from single loss scenarios and inter-frame dependencies. In this work, we evaluate the accuracy of our algorithm by comparing it with the exact calculation of the SSIM metric for different frame loss scenarios. We further consider different high definition test video sequences and group of picture structures and investigate the influence on the accuracy of our proposed approximation.
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Menth, M., Hartmann, M., Klein, D.: Global Locator, Local Locator, and Identifier Split (GLI-Split). Future Internet. 5, 67-94 (2013).
The locator/identifier split is an approach for a new addressing and routing architecture to make routing in the core of the Internet more scalable. Based on this principle, we developed the GLI-Split framework, which separates the functionality of current IP addresses into a stable identifier and two independent locators, one for routing in the Internet core and one for edge networks. This makes routing in the Internet more stable and provides more flexibility for edge networks. GLI-Split can be incrementally deployed and it is backward-compatible with the IPv6 Internet. We describe its architecture, compare it to other approaches, present its benefits, and finally present a proof-of-concept implementation of GLI-Split.
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Klein, D.: An OpenFlow Extension for the OMNeT++ INET Framework. , 6th International Workshop on OMNeT++, Cannes, France (2013).
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Klein, D., Tran-Gia, P.: Big Data: Definition und Stand der Entwicklung. , Datev Trendscout, Nürnberg (2013).
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Klein, D., Tran-Gia, P., Hartmann, M.: Aktuelles Schlagwort: Big Data. Informatik-Spektrum. 36, 319-323 (2013).
Big Data ist neben Cloud Computing und Crowdsourcing eine der wichtigsten neuen Technologie-Treiber und wird daher im Aktuellen Schlagwort näher beleuchtet. Zu Beginn gehen wir auf die Definition von Big Data ein und erläutern die Unterschiede zu traditionellen Verfahren. Im Anschluss daran stellen wir zugrundeliegende Technologien vor und geben einen kurzen Überblick über wissenschaftliche Herausforderungen in diesem Bereich.
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Klein, D., Jarschel, M.: An OpenFlow Extension for the OMNeT++ INET Framework. 6th International Workshop on OMNeT++. , Cannes, France (2013).
Software Defined Networking (SDN) is a new paradigm for communication networks which separates the control plane from the data plane of forwarding elements. This way, SDN constitutes a flexible architecture that allows quick and easy configuration of network devices. This ability is particularly useful when networks have to be adapted to changing traffic volumes of different applications running on the network. OpenFlow is currently the most prominent approach which implements the SDN concept and offers a high flexibility in the routing of network flows. In this paper, we describe the implementation of our model of the OpenFlow system in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we use the simulation model to assess the round-trip-times in a theoretical OpenFlow deployment in a real topology of a North-American Testbed.
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Klein, D., Zinner, T., Lange, S., Singeorzan, V., Schmid, M.: Video Quality Monitoring based on Precomputed Frame Distortions. IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan). , Ghent, Belgium (2013).
In the past decade, video streaming has taken over a large part of the current Internet traffic and more and more TV broadcasters and network providers extend their portfolio of video streaming services. With the growing expectations of video consumers with respect to the service quality, monitoring is an important aspect for network providers to detect possible performance problems or high network load. In parallel, emerging technologies like software defined networking or network virtualization introduce support for specialized networks which allow enhanced functionality in the network. This development enables more sophisticated monitoring techniques in the specialized networks which use knowledge about the video content to better predict the service quality at consumers. In this work, we present a content-aware SSIM-based monitoring technique and compare it with the current state-of-the art which infers the service quality from the monitored packet loss. We further show how network conditions like packet loss or bursts influence the two different monitoring techniques.
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Klein, D.: Integration of LISP and LISP-MN into INET. , 5th International OMNeT++ Workshop held in conjuntion with Simutools 2012, Desenzano, Italy (2012).
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Klein, D., Pries, R., Scharf, M., Söllner, M., Menth, M.: Modeling and Evaluation of Address Resolution Scalability in VPLS. IEEE ICC 2012 - Next-Generation Networking Symposium. , Ottawa, Canada (2012).
More and more services are provided by large data centers with a potentially very large number of physical or virtual hosts. As the number of hosted services and service consumers increases, also the number of hosts inside a data center raises to cope with the increasing end-user demand. Current data center networks are usually based on Ethernet and mechanisms like load balancing or redundancy between data centers require a transparent connection of these Ethernet networks over a Wide Area Network (WAN). Due to the large number of hosts, these interconnected data center networks face scalability problems on different protocol layers. One such issue, which is currently discussed within the IETF, is the scalability of the link layer Address Resolution Protocol (ARP). This paper studies the control traffic caused by address resolution for interconnected data centers. We develop an analytical model for the ARP traffic between data center locations that takes into account the number of hosts and connected sites. This model can then be used to quantify the ARP traffic for a data center interconnect solution. As an example, we apply our model to Virtual Private LAN Services (VPLS). In addition, we study how an ARP proxy can improve the overall scalability, and we show that a proxy significantly reduces the ARP traffic at VPLS switches.
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Klein, D., Höfling, M., Hartmann, M., Menth, M.: Integration of LISP and LISP-MN into INET. 5th International Workshop on OMNeT++. pp. 299-306. , Desenzano, Italy (2012).
The Locator/Identifier Separation Protocol (LISP) is a new naming and addressing architecture which is currently standardized in the IETF and which is deemed to improve the scalability and flexibility of the current routing architecture. LISP mobile node (LISP-MN) is an extension to the basic LISP architecture and enables mobile nodes to roam into LISP and non-LISP domains. The basic LISP architecture is currently deployed in a beta-network which can be used to test the protocol behavior on a smaller scale. However, a realistic simulation model for the LISP architecture and its various extensions is still missing. Such a simulation model could be used by researchers to quickly test new extensions on a larger scale for different load and network scenarios. In this paper, we describe the implementation of our model of the LISP architecture and its various extensions in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we used the simulation model to assess proposed improvements to LISP-MN and to verify our proposed NAT traversal mechanism for LISP-MN.
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Klein, D., Pries, R., Scharf, M., Söllner, M., Menth, M.: Modeling and Evaluation of Address Resolution Scalability in VPLS, (2012).
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Zinner, T., Klein, D., Hoßfeld, T.: User-Centric Network-Application Interaction for Live HD Video Streaming. 4th International Conference on Mobile Networks and Management (MONAMI 2012). , Hamburg, Germany (2012).
Applications and resource allocation within the network become more and more exible in supporting divergent user demands. This is re ected by state-of-the-art video codecs like H.264/SVC which allow a dynamic adaptation of the video quality and therewith the required network resources. Within the network, techniques like network virtualization and multipath data transport allow exible allocation of network resources based on application demands. This paper outlines the potential of the interaction between application and network with an example of a scalable video streaming service and a multipath transport network.
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Klein, D., Menth, M., Pries, R., Tran-Gia, P., Scharf, M., Söllner, M.: A Subscription Model for Time-Scheduled Data Transfers. 12th IFIP/IEEE International Symposium on Integrated Network Management (IM 2011). , Dublin, Ireland (2011).
We recently witness new services that can afford some delay until data transmission starts, but then benefit from a very large available bandwidth. A popular example is the migration of virtual machines between different sites of a geographically dispersed service provider. In this paper, we propose a subscription model for time-scheduled data transfers. Transmission requests are served consecutively, giving the flows access to the physical bandwidth. This is in contrast to today's Internet where flows are served in parallel so that they compete for the available bandwidth. We present the architecture to enable such data beams. Furthermore, we model and analyze the performance under different conditions and compare it with concurrent transmission.
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Zinner, T., Klein, D., Tutschku, K., Zseby, T., Tran-Gia, P., Shavitt, Y.: Performance of Concurrent Multipath Transmissions - Measurements and Model Validation. Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). , Kaiserslautern, Germany (2011).
Concurrent multipath transport layer mechanisms have gained recently increasing interest in research and standardization because of the potential for bandwidth aggregation, load balancing and increased reliability. Multihomed end devices may benefit from IP-based multipath protocols like Multipath TCP or Concurrent Multipath Transmission via SCTP. In the future, concurrent multipath transport might be transparent to network and transport layer protocols as proposed by the concept of Transport Virtualization. This mechanism enables the pooling of heterogeneous transmission technologies or physical paths. However, the selection and application of multiple paths and its impact on the transmission is non-intuitive. Our prior work on transport virtualization discussed the impact of delay diversity of pooled paths on concurrent data transmissions. A mathematical model was introduced enabling the analysis of packet re-ordering that occurs due to different path delays. In this paper we extend our investigations by validating the previously presented analytical and simulative models with measurements performed in Planetlab Europe and the Etomic testbed.
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Klein, D.: A Subscription Model for Time-Scheduled Data Transfers. , EuroNF Plenary Meeting, Soccer Stadium Kaiserslautern (2011).
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Jarschel, M., Klein, D.: Evaluating OpenFlow Performance using Queueing Models, (2011).
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Klein, D.: A Subscription Model for Time-Scheduled Data Transfers. , 12th IFIP/IEEE International Symposium on Integrated Network Management, Dublin, Ireland (2011).
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Menth, M., Hartmann, M., Klein, D.: Global Locator, Local Locator, and Identifier Split (GLI-Split). University of Wuerzburg (2010).
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Klein, D., Tutschku, K., Zinner, T.: Measurement-based Topology and Performance Investigations of D-A-CH Research Networks. University of Wuerzburg (2010).
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Klein, D., Hartmann, M., Höfling, M., Menth, M.: Improvements to LISP Mobile Node Including NAT Traversal, (2010).
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Menth, M., Klein, D., Hartmann, M.: Improvements to LISP Mobile Node, (2010).
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Klein, D.: NAT Traversal for LISP Mobile Node. , ACM CoNEXT workshop Re-Architecting the Internet (ReArch), Philadelphia, PA, USA (2010).
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Pries, R., Klein, D.: Neue Ansätze für Massendatentransfer. , Datev Trendscout, Nürnberg (2010).
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Klein, D.: Improvements to LISP Mobile Node. , 22nd International Teletraffic Congress (ITC22), Amsterdam, The Netherlands (2010).
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Klein, D., Hartmann, M., Menth, M.: NAT Traversal for LISP Mobile Node. ACM CoNEXT workshop Re-Architecting the Internet (ReArch). , Philadelphia, PA, USA (2010).
The Locator/ID Separation Protocol (LISP) is currently being developed and standardized in the IETF aiming to solve the Internet's routing scaling problem. It separates global routing in the Internet from local routing in end-user networks (so-called LISP-domains). It also provides additional benefits like simplified multihoming or the avoidance of network renumbering. The basic LISP architecture does not support mobility. Recently, the mobility extension LISP Mobile Node (LISP-MN) was presented. It describes a mechanism that enables LISP mobile nodes to roam into LISP and non-LISP networks while being reachable under the same identifier address. Currently, LISP-MN does not support networks that use network address translation (NAT). In this paper, we present a NAT traversal mechanism for LISP mobile nodes and a slight adaptation which is also applicable to stationary LISP domains behind a NAT.
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Menth, M., Klein, D., Hartmann, M.: Improvements to LISP Mobile Node. 22nd International Teletraffic Congress (ITC). , Amsterdam, The Netherlands (2010).
The Locator/Identifier Separation Protocol (LISP) is a new routing architecture for the Internet that separates local and global routing. It offers more flexibility to edge networks and has the potential to reduce the growths of the BGP routing tables. Recently, a concept for mobility in LISP (LISP Mobile Node, LISP-MN) was presented. We analyze LISP-MN and show that it needs double mapping lookups in all LISP gateways, leads to triangle routing under some conditions, and requires double encapsulation. We propose gradual improvements to LISP-MN that avoid these drawbacks under many conditions.
