TY - CONF AB - Video streaming is in high demand by mobile users. In cellular networks, however, the unreliable wireless channel leads to two major problems. Poor channel states degrade video quality and interrupt the playback when a user cannot sufficiently fill its local playout buffer: buffer underruns occur. In contrast, good channel conditions cause common greedy buffering schemes to buffer too much data. Such over-buffering wastes expensive wireless channel capacity. Assuming that we can anticipate future data rates, we plan the quality and download time of video segments ahead. This anticipatory download scheduling avoids buffer underruns by downloading a large number of segments before a drop in available data rate occurs, without wasting wireless capacity by excessive buffering.We developed a practical anticipatory scheduling algorithm for segmented video streaming protocols (e.g., HLS or MPEG DASH). Simulation results and testbed measurements show that our solution essentially eliminates playback interruptions without significantly decreasing video quality. AU - Dräxler, Martin AU - Blobel, Johannes AU - Dreimann, Philipp AU - Valentin, Stefan AU - Karl, Holger ID - 252 T2 - Proceedings of the 2nd International Conference on Networked Systems (NetSys) TI - SmarterPhones: Anticipatory Download Scheduling for Wireless Video Streaming ER - TY - CONF AB - The size of modern data centers is constantly increasing. As it is not economic to interconnect all machines in the data center using a full-bisection-bandwidth network, techniques have to be developed to increase the efficiency of data-center networks. The Software-Defined Network paradigm opened the door for centralized traffic engineering (TE) in such environments. Up to now, there were already a number of TE proposals for SDN-controlled data centers that all work very well. However, these techniques either use a high amount of flow table entries or a high flow installation rate that overwhelms available switching hardware, or they require custom or very expensive end-of-line equipment to be usable in practice. We present HybridTE, a TE technique that uses (uncertain) information about large flows. Using this extra information, our technique has very low hardware requirements while maintaining better performance than existing TE techniques. This enables us to build very low-cost, high performance data-center networks. AU - Wette, Philip AU - Karl, Holger ID - 287 T2 - Proceedings of the 4th European Workshop on Software Defined Networks (EWSDN 2015) TI - HybridTE: Traffic Engineering for Very Low-Cost Software-Defined Data-Center Networks ER - TY - CONF AB - Multi-rooted trees are becoming the norm for modern data-center networks. In these networks, scalable flow routing is challenging owing to vast number of flows. Current approaches either employ a central controller that can have scalability issues or a scalable decentralized algorithm only considering local information. In this paper we present a new decentralized approach to least-congested path routing in software-defined data center networks that has neither of these issues: By duplicating the initial (or SYN) packet of a flow and estimating the data rate of multiple flows in parallel, we exploit TCP’s habit to fill buffers to find the least congested path. We show that our algorithm significantly improves flow completion time without the need for a central controller or specialized hardware. AU - Schwabe, Arne AU - Karl, Holger ID - 247 T2 - Proceedings of the 4th European Workshop on Software Defined Networks (EWSDN 2015) TI - SynRace: Decentralized Load-Adaptive Multi-path Routing without Collecting Statistics ER - TY - THES AU - Wette, Philip ID - 264 TI - Optimizing Software-Defined Networks using Application-Layer Knowledge ER - TY - CONF AU - A. Aranda-Gutierrez, Pedro AU - Karl, Holger AU - Rojas, Elisa AU - Leckey, Alec ID - 739 T2 - 2015 European Conference on Networks and Communications, EuCNC 2015, Paris, France, June 29 - July 2, 2015 TI - On Network Application representation and controller independence in {SDN ER - TY - CONF AU - Blanckenstein, Johannes AU - Nardin, Cristina AU - Klaue, Jirka AU - Karl, Holger ID - 742 T2 - {IEEE} International Conference on Communication, {ICC} 2015, London, United Kingdom, June 8-12, 2015, Workshop Proceedings TI - Error characterization of multi-access point WSNs in an aircraft cabin ER - TY - CONF AU - Schwabe, Arne AU - Karl, Holger ID - 743 T2 - 2015 IEEE International Conference on Communications, ICC 2015, London, United Kingdom, June 8-12, 2015 TI - Topology model to generate realistic latency for simulations ER - TY - CONF AU - Dräxler, Martin AU - Blobel, Johannes AU - Karl, Holger ID - 745 T2 - 8th IFIP Wireless and Mobile Networking Conference, WMNC 2015, Munich, Germany, October 5-7, 2015 TI - Anticipatory Download Scheduling in Wireless Video Streaming with Uncertain Data Rate Prediction ER - TY - CONF AU - Wette, Philip AU - Schwabe, Arne AU - Splietker, Malte AU - Karl, Holger ID - 746 T2 - Proceedings of the 1st {IEEE} Conference on Network Softwarization, NetSoft 2015, London, United Kingdom, April 13-17, 2015 TI - Extending Hadoop's Yarn Scheduler Load Simulator with a highly realistic network & traffic model ER - TY - CONF AU - Auroux, Sébastien AU - Karl, Holger ID - 747 T2 - 26th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2015, Hong Kong, China, August 30 - September 2, 2015 TI - Flexible reassignment of flow processing-aware controllers in future wireless networks ER - TY - CONF AU - Auroux, Sébastien AU - Karl, Holger ID - 748 T2 - 2015 IEEE Wireless Communications and Networking Conference, WCNC 2015, New Orleans, LA, USA, March 9-12, 2015 TI - Efficient flow processing-aware controller placement in future wireless networks ER - TY - GEN AU - Dräxler, Sevil AU - Karl, Holger ID - 749 T2 - CoRR TI - Specification of Complex Structures in Distributed Service Function Chaining Using a YANG Data Model ER - TY - GEN AU - Dräxler, Martin AU - Karl, Holger ID - 750 T2 - CoRR TI - Dynamic Backhaul Network Configuration in SDN-based Cloud RANs ER - TY - CONF AB - The increasing amount of mobile traffic leads to a significantly higher energy consumption of mobile networks that is mainly caused by the high number of required base stations. One recent solution for this is based on a two-layered network that uses long-range macro cells to provide a full coverage signaling overlay and short-range small cells for fast data transmissions. These small cells can be switched off when they are not needed and allow network-wide energy optimizations. This paper presents an architecture that extends existing mobile networks to integrate a small cell layer that supports on-demand cell activation. We discuss how additional small cells can be interconnected with existing core components and how they can be controlled by a resource management component. Finally, a Wi-Fi based proof of concept testbed implementation is presented that demonstrates the feasibility of the approach. AU - Peuster, Manuel AU - Karl, Holger ID - 986 T2 - Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges TI - An Architecture for Energy-aware On-demand Mobile Network Management ER - TY - CONF AU - Auroux, Sébastien AU - Draxler, Martin AU - Morelli, Arianna AU - Mancuso, Vincenzo ID - 1636 SN - 9781467373593 T2 - 2015 European Conference on Networks and Communications (EuCNC) TI - Dynamic network reconfiguration in wireless DenseNets with the CROWD SDN architecture ER - TY - CONF AB - Network emulations are widely used for testing novel network protocols and routing algorithms in realistic scenarios. Up to now, there is no emulation tool that is able to emulate large software-defined data center networks that consist of several thousand nodes. Mininet is the most common tool to emulate Software-Defined Networks of several hundred nodes. We extend Mininet to span an emulated network over several physical machines, making it possible to emulate networks of several thousand nodes on just a handful of physical machines. This enables us to emulate, e.g., large data center networks. To test this approach, we additionally introduce a traffic generator for data center traffic. Since there are no data center traffic traces publicly available we use the results of two recent traffic studies to create synthetic traffic. We show the design and discuss some challenges we had in building our traffic generator. As a showcase for our work we emulated a data center consisting of 3200 hosts on a cluster of only 12 physical machines. We show the resulting workloads and the trade-offs involved. AU - Wette, Philip AU - Dräxler, Martin AU - Schwabe, Arne AU - Wallaschek, Felix AU - Zahraee, Mohammad Hassan AU - Karl, Holger ID - 329 T2 - Proceedings of the 2014 IFIP Networking Conference (Networking 2014) TI - MaxiNet: Distributed Emulation of Software-Defined Networks ER - TY - CONF AB - Preemptive Routing and Wavelength Assignment (RWA) algorithms preempt established lightpaths in case notenough resources are available to set up a new lightpath in aWavelength Division Multiplexing (WDM) network. The selectionof lightpaths to be preempted relies on internal decisions of theRWA algorithm. Thus, if dedicated properties of the networktopology are required by the applications running on the network,these requirements have to be known to the RWA algorithm.We present a family of preemptive RWA algorithms for WDMnetworks. These algorithms have two distinguishing features: a)they can handle dynamic traffic by on-the-fly reconfiguration,and b) users can give feedback for reconfiguration decisions andthus influence the preemption decision of the RWA algorithm,leading to networks which adapt directly to application needs.This is different from traffic engineering where the network is(slowly) adapted to observed traffic patterns.Our algorithms handle various WDM network configurationsincluding networks consisting of heterogeneous WDM hardware.To this end, we are using the layered graph approach togetherwith a newly developed graph model that is used to determineconflicting lightpaths. AU - Wette, Philip AU - Karl, Holger ID - 339 T2 - Proceedings of the IEEE International Conference on Communications 2014 TI - Using Application Layer Knowledge in Routing and Wavelength Assignment Algorithms ER - TY - THES AU - Künsemöller, Jörn ID - 343 TI - Tragedy of the Common Cloud - Game Theory on the Infrastructure-as-a-Service Market ER - TY - CONF AB - In distributed cloud computing, application deployment across multiple sites can improve quality of service. Recent research developed algorithms to find optimal locations for virtual machines. However, those algorithms assume to have either single-tier applications or a fixed number of virtual machines – a strong simplification of reality. This paper investigates the placement and scaling of complex application architectures. An application is dynamically scaled to fit both the current demand situation and the currently available infrastructure resources. We compare two approaches: The first one is based on virtual network embedding. The second approach is a novel method called Template Embedding. It is based on a hierarchical 1-allocation hub flow problem and combines applica- tion scaling and embedding in one step. Extensive experiments on 43200 network configurations showed that Template Embedding outperforms virtual network embedding in all cases in three metrics: success rate, solution quality, and runtime. This positive result shows that template embedding is a promising approach for distributed cloud resource allocation. AU - Keller, Matthias AU - Robbert, Christoph AU - Karl, Holger ID - 354 T2 - Proceedings of 7th International Conference on Utility and Cloud Computing (UCC) TI - Template Embedding: Using Application Architecture to Allocate Resources in Distributed Clouds ER - TY - CONF AB - Network appliances perform different functions on network flows and constitute an important part of an operator’s network. Normally, a set of chained network functions process network flows. Following the trend of virtualization of networks, virtualization of the network functions has also become a topic of interest. We define a model for formalizing the chaining of network functions using a context-free language. We process deployment requests and construct virtual network function graphs that can be mapped to the network. We describe the mapping as a Mixed Integer Quadratically Constrained Program (MIQCP) for finding the placement of the network functions and chaining them together considering the limited network resources and requirements of the functions. We have performed a Pareto set analysis to investigate the possible trade-offs between different optimization objectives. AU - Dräxler, Sevil AU - Keller, Matthias AU - Karl, Holger ID - 360 T2 - Proceedings of the 3rd International Conference on Cloud Networking (CloudNet) TI - Specifying and Placing Chains of Virtual Network Functions ER - TY - GEN AU - Roeske, Daniel ID - 361 TI - Simulating load-dependent operation of picocells ER - TY - CONF AB - In the near future many more compute resources will be available at different geographical locations. To minimize the response time of requests, application servers closer to the user can hence be used to shorten network round trip times. However, this advantage is neutralized if the used data centre is highly loaded as the processing time of re- quests is important as well. We model the request response time as the network round trip time plus the processing time at a data centre.We present a capacitated facility location problem formal- ization where the processing time is modelled as the sojourn time of a queueing model. We discuss the Pareto trade-off between the number of used data centres and the resulting response time. For example, using fewer data centres could cut expenses but results in high utilization, high response time, and smaller revenues.Previous work presented a non-linear cost function. We prove its convexity and exploit this property in two ways: First, we transform the convex model into a linear model while controlling the maximum approximation error. Sec- ond, we used a convex solver instead of a slower non-linear solver. Numerical results on network topologies exemplify our work. AU - Keller, Matthias AU - Karl, Holger ID - 372 T2 - Proceedings of the SIGCOMM workshop on Distributed cloud computing TI - Response Time-Optimized Distributed Cloud Resource Allocation ER - TY - THES AB - Radio access networks (RANs) have become one of the largest energy consumers of communication technology [LLH+13] and their energy consumption is predicted to increase [FFMB11]. To reduce the energy consumption of RANs different techniques have been proposed. One of the most promising techniques is the use of a low-power sleep mode. However, a sleep mode can also reduce the performance. In this dissertation, I quantify how much energy can be conserved with a sleep mode and which negative effects it has on the performance of RANs. Additionally, I analyze how a sleep mode can be enabled more often and how the performance can be kept high. First, I quantify the effect of power-cycle durations on energy consumption and latency in an abstract queuing system. This results in a trade-off between energy consumption and latency for a single base station (BS). Second, I show that considering a network as a whole (instead of each BS individually) allows the energy consumption to be reduced even further. After these analyses, which are not specific for RANs, I study RANs for the rest of the dissertation. RANs need to both detect and execute the requests of users. Because detection and execution of requests have different requirements, I analyze them independently. I quantify how the number of active BSs can be reduced if the detection ranges of BSs are increased by cooperative transmissions. Next, I analyze how more BSs can be deactivated if the remaining active BSs cooperate to transmit data to the users. However, in addition to increasing the range, cooperative transmissions also radiate more power. This results in higher interference for other users which slows their transmissions down and, thus, increases energy consumption. Therefore, I describe how the radiated power of cooperative transmissions can be reduced if instantaneous channel knowledge is available. Because the implementation in real hardware is impractical for demonstration purposes, I show the results of a simulation that incorporates all effects I studied analytically earlier. In conclusion, I show that a sleep mode can reduce the energy consumption of RANs if applied correctly. To apply a sleep mode correctly, it is necessary to consider power-cycle durations, power profiles, and the interaction of BSs. When this knowledge is combined the energy consumption of RANs can be reduced with only a slight loss of performance. Because this results in a trade-off between energy consumption and performance, each RAN operator has to decide which trade-off is preferred. AU - Herlich, Matthias ID - 376 TI - Reducing Energy Consumption of Radio Access Networks ER - TY - CONF AB - This paper explores how cloud provider competition influences instance pricing in an IaaS (Infrastructure-as-a-Service) market. When reserved instance pricing includes an on-demand price component in addition to a reservation fee (two-part tariffs), different providers might offer different price combinations, where the client’s choice depends on its load profile. We investigate a duopoly of providers and analyze stable market prices in two-part tariffs. Further, we study offers that allow a specified amount of included usage (three-part tariffs). Neither two-part nor three-part tariffs produce an equilibrium market outcome other than a service pricing that equals production cost, i.e., complex price structures do not significantly affect the results from ordinary Bertrand competition. AU - Künsemöller, Jörn AU - Brangewitz, Sonja AU - Karl, Holger AU - Haake, Claus-Jochen ID - 382 T2 - Proceedings of the 2014 IEEE International Conference on Services Computing (SCC) TI - Provider Competition in Infrastructure-as-a-Service ER - TY - CONF AU - Wette, Philip AU - Karl, Holger ID - 1801 SN - 9781479900565 T2 - 2013 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS) TI - Incorporating feedback from application layer into routing and wavelength assignment algorithms ER - TY - GEN AU - Dreimann, Philipp ID - 458 TI - Anticipatory Power Cycling of Mobile Network Equipment for High-Demand Multimedia Traffic ER - TY - GEN AU - Dräxler, Sevil ID - 461 TI - Adaptive Placement of Programmable Virtual Network Function Chains ER - TY - JOUR AB - Financial benefits are an important factor when cloud infrastructure is considered to meet processing demand. The dynamics of on-demand pricing and service usage are investigated in a two-stage game model for a monopoly Infrastructure-as-a-Service (IaaS) market. The possibility of hybrid clouds (public clouds plus own infrastructure) turns out to be essential in order that not only the provider but also the clients have significant benefits from on-demand services. Even if the client meets all demand in the public cloud, the threat of building a hybrid cloud keeps the instance price low. This is not the case when reserved instances are offered as well. Parameters like load profiles and economies of scale have a huge effect on likely future pricing and on a cost-optimal split-up of client demand between either a client’s own data center and a public cloud service or between reserved and on-demand cloud instances. AU - Künsemöller, Jörn AU - Karl, Holger ID - 467 JF - Future Generation Computer Systems TI - A Game-Theoretic Approach to the Financial Benefits of Infrastructure-as-a-Service ER - TY - JOUR AU - Beister, Frederic AU - Dräxler, Martin AU - Aelken, J. AU - Karl, Holger ID - 753 JF - Computer Communications TI - Power model design for ICT systems -- A generic approach ER - TY - JOUR AU - Azeem M. Khan, Rana AU - Karl, Holger ID - 754 IS - 1 JF - IEEE Communications Surveys and Tutorials TI - MAC Protocols for Cooperative Diversity in Wireless LANs and Wireless Sensor Networks ER - TY - CONF AU - Dräxler, Martin AU - Dreimann, Philipp AU - Karl, Holger ID - 759 T2 - IEEE Online Conference on Green Communications, OnlineGreenComm 2014, November 12-14, 2014 TI - Anticipatory power cycling of mobile network equipment for high demand multimedia traffic ER - TY - CONF AU - Auroux, Sebastien AU - Karl, Holger ID - 760 T2 - 25th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communication, {PIMRC} 2014, Washington DC, USA, September 2-5, 2014 TI - Flow processing-aware controller placement in wireless DenseNets ER - TY - CONF AU - Schwabe, Arne AU - Karl, Holger ID - 762 T2 - Proceedings of the third workshop on Hot topics in software defined networking, HotSDN '14, Chicago, Illinois, USA, August 22, 2014 TI - Using MAC addresses as efficient routing labels in data centers ER - TY - CONF AU - Blanckenstein, Johannes AU - Karl, Holger ID - 763 T2 - 22nd International Conference on Software, Telecommunications and Computer Networks, SoftCOM 2014, Split, Croatia, September 17-19, 2014 TI - Energy-efficient clock synchronization using wake-up receivers ER - TY - CONF AU - Beister, Frederic AU - Karl, Holger ID - 765 T2 - IEEE 10th International Conference on Wireless and Mobile Computing, Networking and Communications, WiMob 2014, Larnaca, Cyprus, October 8-10, 2014 TI - Predicting mobile video inter-download times with Hidden Markov Models ER - TY - GEN AU - Mehraghdam, Sevil AU - Keller, Matthias AU - Karl, Holger ID - 766 T2 - CoRR TI - Specifying and Placing Chains of Virtual Network Functions ER - TY - GEN AU - Wette, Philip AU - Karl, Holger ID - 767 T2 - CoRR TI - DCT²Gen: A Versatile TCP Traffic Generator for Data Centers ER - TY - GEN AU - Schwabe, Arne AU - Karl, Holger ID - 768 T2 - CoRR TI - Adding Geographical Embedding to AS Topology Generation ER - TY - GEN AU - Dornseifer, Veit ID - 426 TI - Evaluation of a Hybrid Packet-/Circuit-Switched Data Center Network ER - TY - GEN AU - Bredenbals, Nico ID - 432 TI - Energy-Efficient Queuing with Delayed Deactivation ER - TY - CONF AU - Dräxler, Martin AU - Karl, Holger ID - 1647 T2 - Proceedings of 20th European Wireless Conference TI - Feasibility of Base Station Coordination and Dynamic Backhaul Network Configuration in Backhaul Networks with Limited Capacity ER - TY - CONF AU - Herlich, Matthias AU - Karl, Holger ID - 1654 SN - 9783901882630 T2 - 12th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt) 2014 TI - Analytic quantification of outage probability and radiated power of cooperative base stations ER - TY - JOUR AU - Beister, Frederic AU - Dräxler, Martin AU - Aelken, Jörg AU - Karl, Holger ID - 1375 JF - Computer Communications SN - 0140-3664 TI - Power model design for ICT systems – A generic approach VL - 50 ER - TY - CONF AU - Keller, Matthias AU - Robbert, Christoph AU - Peuster, Manuel ID - 1798 T2 - Proceedings of the ACM SIGCOMM 2013 conference on SIGCOMM TI - An evaluation testbed for adaptive, topology-aware deployment of elastic applications ER - TY - CONF AU - Ali-Ahmad, Hassan AU - Cicconetti, Claudio AU - de la Oliva, Antonio AU - Draxler, Martin AU - Gupta, Rohit AU - Mancuso, Vincenzo AU - Roullet, Laurent AU - Sciancalepore, Vincenzo ID - 1799 SN - 9781479924332 T2 - 2013 Second European Workshop on Software Defined Networks TI - CROWD: An SDN Approach for DenseNets ER - TY - CHAP AU - Blanckenstein, Johannes AU - Garcia-Jimenez, Javier AU - Klaue, Jirka AU - Karl, Holger ID - 1800 SN - 1876-1100 T2 - Lecture Notes in Electrical Engineering TI - A Scalable Redundant TDMA Protocol for High-Density WSNs Inside an Aircraft ER - TY - CONF AU - Wette, P. AU - Graffi, K. ID - 1802 SN - 9781467356459 T2 - 2013 Conference on Networked Systems TI - Adding Capacity-Aware Storage Indirection to Homogeneous Distributed Hash Tables ER - TY - CONF AU - Dannewitz, Christian AU - Herlich, Matthias AU - Karl, Holger ID - 1803 SN - 9781467321297 T2 - 37th Annual IEEE Conference on Local Computer Networks -- Workshops TI - OpenNetInf - prototyping an information-centric Network Architecture ER - TY - CHAP AU - de la Oliva, Antonio AU - Morelli, Arianna AU - Mancuso, Vincenzo AU - Draexler, Martin AU - Hentschel, Tim AU - Melia, Telemaco AU - Seite, Pierrick AU - Cicconetti, Claudio ID - 1804 SN - 1867-8211 T2 - Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering TI - Denser Networks for the Future Internet, the CROWD Approach ER - TY - JOUR AU - Dannewitz, Christian AU - Kutscher, Dirk AU - Ohlman, B AU - Farrell, Stephen AU - Ahlgren, Bengt AU - Karl, Holger ID - 770 IS - 7 JF - Computer Communications TI - Network of Information (NetInf) - An information-centric networking architecture ER - TY - JOUR AU - Dräxler, Martin AU - Biermann, Thorsten AU - Karl, Holger ID - 771 IS - 3 JF - International Journal of Wireless Information Networks TI - Improving Cooperative Transmission Feasibility by Network Reconfiguration in Limited Backhaul Networks ER - TY - CONF AU - Hohenberger, Till AU - Herlich, Matthias AU - Karl, Holger ID - 772 T2 - IEEE International Conference on Advanced Networks and Telecommunications Systems, ANTS 2013, Kattankulathur, India, December 15-18, 2013 TI - Trade-off between latency and coverage in cooperative radio access networks ER - TY - CONF AU - M. Facca, Federico AU - Salvadori, Elio AU - Karl, Holger AU - R. Lopez, Diego AU - Arranda Gutierrez, Pedro AU - Kostic, Dejan AU - Riggio, Roberto ID - 773 T2 - Second European Workshop on Software Defined Networks, EWSDN 2013, Berlin, Germany, October 10-11, 2013 TI - NetIDE: First Steps towards an Integrated Development Environment for Portable Network Apps ER - TY - CONF AU - Cicconetti, Claudio AU - Morelli, Arianna AU - Dräxler, Martin AU - Karl, Holger AU - Mancuso, Vincenzo AU - Sciancalepore, Vincenzo AU - Gupta, Rohit AU - de la Oliva, Antonio AU - Isabel Sanchez, M. AU - Serrano, Pablo AU - Roullet, Laurent ID - 774 T2 - 2013 Future Network & Mobile Summit, Lisboa, Portugal, July 3-5, 2013 TI - The playground of Wireless Dense networks of the future ER - TY - CONF AU - Keller, Matthias AU - Peuster, Manuel AU - Robbert, Christoph AU - Karl, Holger ID - 775 T2 - 17th International Conference on Intelligence in Next Generation Networks, {ICIN} 2013, Venice, Italy, October 15-16, 2013 TI - A topology-aware adaptive deployment framework for elastic applications ER - TY - CONF AU - Herlich, Matthias AU - Karl, Holger ID - 776 T2 - ISWCS 2013, The Tenth International Symposium on Wireless Communication Systems, Ilmenau, Germany, August 27-30, 2013 TI - Energy-Efficient Assignment of User Equipment to Cooperative Base Stations ER - TY - CONF AU - Dräxler, Martin AU - Karl, Holger ID - 777 T2 - 2013 9th International Wireless Communications and Mobile Computing Conference, IWCMC 2013, Sardinia, Italy, July 1-5, 2013 TI - Cross-layer scheduling for multi-quality video streaming in cellular wireless networks ER - TY - GEN AU - Dräxler, Martin AU - Blobel, Johannes AU - Dreimann, Philipp AU - Valentin, Stefan AU - Karl, Holger ID - 781 T2 - CoRR TI - Anticipatory Buffer Control and Quality Selection for Wireless Video Streaming ER - TY - CONF AB - In OpenFlow [1], multiple switches share the same control plane which is centralized atwhat is called the OpenFlow controller. A switch only consists of a forwarding plane. Rules for forwarding individual packets (called ow entries in OpenFlow) are pushed from the controller to the switches. In a network with a high arrival rate of new ows, such as in a data center, the control trac between the switch and controller can become very high. As a consequence, routing of new ows will be slow. One way to reduce control trac is to use wildcarded ow entries. Wildcard ow entries can be used to create default routes in the network. However, since switches do not keep track of ows covered by a wildcard ow entry, the controller no longer has knowledge about individual ows. To nd out about these individual ows we propose an extension to the current OpenFlow standard to enable packet sampling of wildcard ow entries. AU - Wette, Philip AU - Karl, Holger ID - 470 T2 - Proceedings of the ACM SIGCOMM '13 TI - Which Flows Are Hiding Behind My Wildcard Rule? Adding Packet Sampling to OpenFlow ER - TY - GEN AU - Wallaschek, Felix ID - 490 TI - Routing in heterogenen OpenFlow Netzwerken ER - TY - GEN AU - Robbert, Christoph ID - 492 TI - Ressource-Optimized Deployment of Multi-Tier Applications - The Data Rate-Constrained Case ER - TY - CONF AB - Within reactive topology control, a node determines its adjacent edges of a network subgraph without prior knowledge of its neighborhood. The goal is to construct a local view on a topology which provides certain desired properties such as planarity. During algorithm execution, a node, in general, is not allowed to determine all its neighbors of the network graph. There are well-known reactive algorithms for computing planar subgraphs. However, the subgraphs obtained do not have constant Euclidean spanning ratio. This means that routing along these subgraphs may result in potentially long detours. So far, it has been unknown if planar spanners can be constructed reactively. In this work, we show that at least under the unit disk network model, this is indeed possible, by proposing an algorithm for reactive construction of the partial Delaunay triangulation, which recently turned out to be a spanner. Furthermore, we show that our algorithm is message-optimal as a node will only exchange messages with nodes that are also neighbors in the spanner. The algorithm’s presentation is complemented by a rigorous proof of correctness. AU - Benter, Markus AU - Neumann, Florentin AU - Frey, Hannes ID - 496 T2 - Proceedings of the 32nd IEEE International Conference on Computer Communications (INFOCOM) TI - Reactive Planar Spanner Construction in Wireless Ad Hoc and Sensor Networks ER - TY - JOUR AU - Biermann, Thorsten AU - Scalia, Luca AU - Choi, Changsoon AU - Kellerer, Wolfgang AU - Karl, Holger ID - 769 IS - 8 JF - {IEEE} Communications Magazine TI - How backhaul networks influence the feasibility of coordinated multipoint in cellular networks ER - TY - CONF AB - The process of planning a virtual topology for a Wavelength Devision Multiplexing (WDM) network is called Virtual Topology Design (VTD). The goal of VTD is to find a virtual topology that supports forwarding the expected traffic without congestion. In networks with fluctuating, high traffic demands, it can happen that no single topology fits all changing traffic demands occurring over a longer time. Thus, during operation, the virtual topology has to be reconfigured. Since modern networks tend to be large, VTD algorithms have to scale well with increasing network size, requiring distributed algorithms. Existing distributed VTD algorithms, however, react too slowly on congestion for the real-time reconfiguration of large networks. We propose Selfish Virtual Topology Reconfiguration (SVTR) as a new algorithm for distributed VTD. It combines reconfiguring the virtual topology and routing through a Software Defined Network (SDN). SVTR is used for online, on-the-fly network reconfiguration. Its integrated routing and WDM reconfiguration keeps connection disruption due to network reconfiguration to a minimum and is able to react very quickly to traffic pattern changes. SVTR works by iteratively adapting the virtual topology to the observed traffic patterns without global traffic information and without future traffic estimations. We evaluated SVTR by simulation and found that it significantly lowers congestion in realistic networks and high load scenarios. AU - Wette, Philip AU - Karl, Holger ID - 508 T2 - Proceedings of the 19th IEEE International Workshop on Local and Metropolitan Area Networks (IEEE LANMAN) TI - On the Quality of Selfish Virtual Topology Reconfiguration in IP-over-WDM Networks ER - TY - CONF AB - In this paper we will introduce a new d-dimensional graph for constructing geometric application layer overlay net-works. Our approach will use internet coordinates, embedded using the L∞ -metric. After describing the graph structure, we will show how it limits maintenance overhead by bounding each node’s out-degree and how it supports greedy routing using one-hop neighbourhood information in each routing step. We will further show that greedy routing can always compute a path in our graph and we will also prove that in each forwarding step the next hop is closer to the destination than the current node. AU - Autenrieth, Marcus AU - Frey, Hannes ID - 509 T2 - Proceedings of the Conference on Networked Systems (NetSys) TI - On Greedy Routing in Degree-bounded Graphs over d-Dimensional Internet Coordinate Embeddings ER - TY - GEN AU - Splietker, Malte ID - 511 TI - MapReduce in Software Defined Networks ER - TY - CONF AB - Preemptive Routing and Wavelength Assignment (RWA) algorithms preempt established lightpaths in case not enough resources are available to set up a new lightpath in a Wavelength Division Multiplexing (WDM) network. The selection of lightpaths to be preempted relies on internal decisions of the RWA algorithm. Thus, if dedicated properties of the network topology are required by the applications running on the network, these requirements have to be known to the RWA algorithm.Otherwise it might happen that by preempting a particular lightpath these requirements are violated. If, however, these requirements include parametersknown only at the nodes running the application, the RWA algorithm cannot evaluate the requirements. For this reason an RWA algorithm is needed which incorporates feedback from the application layer in the preemption decisions.This work proposes a simple interface along with an algorithm for computing and selecting preemption candidates in case a lightpath cannot be established. We reason about the necessity of using information from the application layer in the RWA and present two example applications which benefit from this idea. AU - Wette, Philip AU - Karl, Holger ID - 520 T2 - Proceedings of the 32nd IEEE International Conference on Computer Communications (INFOCOM) TI - Incorporating feedback from application layer into routing and wavelength assignment algorithms ER - TY - GEN AU - Niklas Vinkemeier, Tim ID - 525 TI - Haptics - Hadoop performance testing in concurrent job scenarios ER - TY - GEN AU - Satya, Suhas ID - 534 TI - Emulating Wavelength Division Multiplexing using Openflow ER - TY - CONF AB - In Distributed Cloud Computing, applications are deployed across many data centres at topologically diverse locations to improved network-related quality of service (QoS). As we focus on interactive applications, we minimize the latency between users and an application by allocating Cloud resources nearby the customers. Allocating resources at all locations will result in the best latency but also in the highest expenses. So we need to find an optimal subset of locations which reduces the latency but also the expenses – the facility location problem (FLP). In addition, we consider resource capacity restrictions, as a resource can only serve a limited amount of users. An FLP can be globally solved. Additionally, we propose a local, distributed heuristic. This heuristic is running within the network and does not depend on a global component. No distributed, local approximations for the capacitated FLP have been proposed so far due to the complexity of the problem. We compared the heuristic with an optimal solution obtained from a mixed integer program for different network topologies. We investigated the influence of different parameters like overall resource utilization or different latency weights. AU - Keller, Matthias AU - Pawlik, Stefan AU - Pietrzyk, Peter AU - Karl, Holger ID - 562 T2 - Proceedings of the 6th International Conference on Utility and Cloud Computing (UCC) workshop on Distributed cloud computing TI - A Local Heuristic for Latency-Optimized Distributed Cloud Deployment ER - TY - GEN AU - Khan, Rana Azeem M. AU - Karl, Holger ID - 2504 TI - Simulating Cooperative Diversity Protocols for Multi-hop Wireless and Sensor Networks ER - TY - GEN AU - Dannewitz, Christian AU - Karl, Holger AU - Yadav, Aditya ID - 2505 TI - Report on Locality in DNS Requests – Evaluation and Impact on Future Internet Architectures ER - TY - CONF AU - Biermann, T. AU - Scalia, L. ID - 1805 SN - 9781424492688 T2 - 2011 IEEE Global Telecommunications Conference - GLOBECOM 2011 TI - Mobile WDM Backhaul Access Networks with Physical Inter-Base-Station Links for Coordinated Multipoint Transmission/Reception Systems ER - TY - CONF AU - Choi, Changsoon AU - Scalia, Luca AU - Biermann, Thorsten AU - Mizuta, Shinj ID - 1806 SN - 9781457713484 T2 - 2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications TI - Coordinated multipoint multiuser-MIMO transmissions over backhaul-constrained mobile access networks ER - TY - JOUR AU - Biermann, Thorsten AU - Scalia, Luca AU - Choi, Changsoon AU - Karl, Holger AU - Kellerer, Wolfgang ID - 782 IS - 5 JF - Pervasive and Mobile Computing TI - CoMP clustering and backhaul limitations in cooperative cellular mobile access networks ER - TY - JOUR AU - Willig, Andreas AU - Karl, Holger AU - Kipnis, Danil ID - 783 IS - 2 JF - Wireless Networks TI - Segment-based packet combining: how to schedule a dense relayer cluster? ER - TY - CONF AU - Herlich, Matthias AU - Karl, Holger ID - 784 T2 - Proceedings of the 3rd International Conference on Energy-Efficient Computing and Networking, e-Energy'12, Madrid, Spain, May 9-11, 2012 TI - Average and competitive analysis of latency and power consumption of a queuing system with a sleep mode ER - TY - CONF AU - Blanckenstein, Johannes AU - Klaue, Jirka AU - Karl, Holger ID - 785 T2 - European Wireless 2012 - 18th European Conference 2012, April 18-20, 2012, Poznan, Poland. TI - Energy Efficient Clustering using a Wake-up Receiver ER - TY - CONF AU - Künsemöller, Jörn AU - Karl, Holger ID - 786 T2 - Economics of Grids, Clouds, Systems, and Services - 9th International Conference, GECON 2012, Berlin, Germany, November 27-28, 2012. Proceedings TI - On Local Separation of Processing and Storage in Infrastructure-as-a-Service ER - TY - CONF AU - Dräxler, Martin AU - Karl, Holger ID - 787 T2 - 2012 IEEE International Conference on Green Computing and Communications, Conference on Internet of Things, and Conference on Cyber, Physical and Social Computing, GreenCom/iThings/CPSCom 2012, Besancon, France, November 20-23, 2012 TI - Efficiency of On-Path and Off-Path Caching Strategies in Information Centric Networks ER - TY - CONF AU - Dannewitz, Christian AU - Herlich, Matthias AU - Karl, Holger ID - 788 T2 - 37th Annual IEEE Conference on Local Computer Networks, Workshop Proceedings, Clearwater Beach, FL, USA, October 22-25, 2012 TI - OpenNetInf - prototyping an information-centric Network Architecture ER - TY - CONF AU - Dräxler, Martin AU - Biermann, Thorsten AU - Karl, Holger AU - Kellerer, Wolfgang ID - 789 T2 - 23rd IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2012, Sydney, Australia, September 9-12, 2012 TI - Cooperating base station set selection and network reconfiguration in limited backhaul networks ER - TY - CONF AU - Dräxler, Martin AU - Beister, Frederic AU - Kruska, Stephan AU - Aelken, J. AU - Karl, Holger ID - 790 T2 - International ICST Conference on Simulation Tools and Techniques, SIMUTOOLS '12, Sirmione-Desenzano, Italy, March 19-23, 2012 TI - Using OMNeT++ for energy optimization simulations in mobile core networks ER - TY - CONF AU - Volkhausen, Tobias AU - Schinköthe, Kai AU - Karl, Holger ID - 791 T2 - 2012 IEEE Wireless Communications and Networking Conference, WCNC 2012, Paris, France, April 1-4, 2012 TI - Quantization techniques for accurate soft message combining ER - TY - CONF AU - Volkhausen, Tobias AU - Dridger, Kornelius AU - S. Lichte, Hermann AU - Karl, Holger ID - 792 T2 - 10th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), Paderborn, Germany, May 14-18, 2012 TI - Efficient cooperative relaying in wireless multi-hop networks with commodity WiFi hardware ER - TY - GEN AU - Hohenberger, Till ID - 584 TI - Queuing Latency at Cooperative Base Stations ER - TY - GEN AU - Rojahn, Tobias ID - 593 TI - Optimale Zuteilung von Nutzern zu verteilten Cloud-Standorten ER - TY - GEN AB - Preemptive Routing and Wavelength Assignment (RWA) algorithms preempt established lightpaths in case not enough resources are available to setup a new lightpath in a Wavelength Division Multiplexing (WDM) network. The selection of lightpaths to be preempted relies on internal decisions of the RWA algorithm. Thus, if dedicated properties of the network topology are required by the applications running on the network, these requirements have to be known by the RWA algorithm. Otherwise it might happen that by preempting a particular lightpath these requirements are violated. If, however, these requirements include parameters only known at the nodes running the application, the RWA algorithm cannot evaluate the requirements. For this reason a RWA algorithm is needed which involves its users in the preemption decisions. We present a family of preemptive RWA algorithms for WDM networks. These algorithms have two distinguishing features: a) they can handle dynamic traffic by on-the-fly reconfiguration, and b) users can give feedback for reconfiguration decisions and thus influence the preemption decision of the RWA algorithm, leading to networks which adapt directly to application needs. This is different from traffic engineering where the network is (slowly) adapted to observed traffic patterns. Our algorithms handle various WDM network configurations including networks consisting of heterogeneous WDM hardware. To this end, we are using the layered graph approach together with a newly developed graph model that is used to determine conflicting lightpaths. AU - Wette, Philip AU - Karl, Holger ID - 603 TI - Introducing feedback to preemptive routing and wavelength assignment algorithms for dynamic traffic scenarios ER - TY - CHAP AU - Dannewitz, Christian AU - al, et ID - 2662 T2 - Architecture and Design for the Future Internet TI - How to manage and Search/Retrieve Information Objects ER - TY - CHAP AU - Dannewitz, Christian AU - al, et ID - 2663 T2 - Architecture and Design for the Future Internet TI - Integrating Generic Paths and NetInf ER - TY - CONF AU - Scalia, Luca AU - Biermann, Thorsten AU - Choi, Changsoon AU - Kozu, Kazuyuki AU - Kellerer, Wolfgang ID - 1807 SN - 9781457702495 T2 - 2011 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS) TI - Power-efficient mobile backhaul design for CoMP support in future wireless access systems ER - TY - CONF AU - Willig, Andreas AU - Kipnis, Danil AU - Karl, Holger ID - 1808 SN - 9781424471744 T2 - 2010 Sixth International Conference on Intelligent Sensors, Sensor Networks and Information Processing TI - Segment-based packet combining in a cluster: To combine or not to combine? ER - TY - CHAP AU - Kanter, Theo AU - Kardeby, Victor AU - Forsström, Stefan AU - Walters, Jamie ID - 1838 SN - 1867-8211 T2 - Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering TI - Scenarios, Research Issues, and Architecture for Ubiquitous Sensing ER - TY - GEN ED - Frey, Hannes ED - Li, Xu ED - R{ührup, Stefan ID - 929 SN - 978-3-642-22449-2 TI - Ad-hoc, Mobile, and Wireless Networks - 10th International Conference, ADHOC-NOW 2011, Paderborn, Germany, July 18-20, 2011. Proceedings ER - TY - JOUR AU - Ahlgren, Bengt AU - A. Aranda-Gutierrez, Pedro AU - Chemouil, Prosper AU - Oueslati, Sara AU - M. Correia, L AU - Karl, Holger AU - Söllner, Michael AU - Welin, Annikki ID - 793 IS - 7 JF - IEEE Communications Magazine TI - Content, connectivity, and cloud: ingredients for the network of the future ER - TY - JOUR AU - Conti, Marco AU - Chong, Song AU - Fdida, Serge AU - Jia, Weijia AU - Karl, Holger AU - Lin, Ying{-}Dar AU - M{\, Petri AU - Maier, Martin AU - Molva, Refik AU - Uhlig, Steve AU - Zukerman, Moshe ID - 794 IS - 18 JF - Computer Communications TI - Research challenges towards the Future Internet ER - TY - CONF AU - D'Ambrosio, Matteo AU - Dannewitz, Christian AU - Karl, Holger AU - Vercellone, Vinicio ID - 795 T2 - 2011 ACM SIGCOMM Workshop on Information-Centric Networking, ICN 2011, Toronto, ON, Canada, August 19, 2011 TI - MDHT: A hierarchical name resolution service for information-centric networks ER - TY - CONF AU - Azeem M. Khan, Rana AU - Karl, Holger ID - 796 T2 - Ad-hoc, Mobile, and Wireless Networks - 10th International Conference, ADHOC-NOW 2011, Paderborn, Germany, July 18-20, 2011. Proceedings TI - Multihop Performance of Cooperative Preamble Sampling MAC(CPS-MAC) in Wireless Sensor Networks ER - TY - CONF AU - Herlich, Matthias AU - Karl, Holger ID - 797 T2 - 2nd International Conference on Energy-Efficient Computing and Networking 2011, e-Energy '11, New York, NY, USA - May 31 - June 01, 2011 TI - Reducing power consumption of mobile access networks with cooperation ER - TY - CONF AU - Künsemöller, Jörn AU - Karl, Holger ID - 798 T2 - Economics of Grids, Clouds, Systems, and Services - 8th International Workshop, GECON 2011, Paphos, Cyprus, December 5, 2011, Revised Selected Papers TI - A Game-Theoretical Approach to the Benefits of Cloud Computing ER -