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  • 1. Fida, Mah-Rukh
    et al.
    Kousias, Konstantinos
    Lutu, Andra
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alay, Ozgu
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Argyriou, Antonios
    FLEX-MONROE: A unified platform for experiments under controlled and operational LTE settings2017In: WiNTECH 2017 Proceedings of the 11th Workshop on Wireless Network Testbeds, Experimental evaluation & CHaracterization, Association for Computing Machinery (ACM), 2017, p. 1-8Conference paper (Refereed)
    Abstract [en]

    This paper presents FLEX-MONROE, a unique platform that facilitates achieving a thorough understanding of LTE networks, one that captures the status of current operational MBB networks and that also enables LTE performance improvements by allowing experimentation in an environment with controllable LTE parameters. Using this platform, we propose to investigate how variations in the LTE network parameters influence the network characteristics, which, in turn, translate to application performance metrics that represent the end-user experience. We argue that the FLEX-MONROE platform is crucial to understand, validate and ultimately improve how current operational MBB networks perform, towards providing guidelines for designing future 5G architectures. Furthermore, understanding the effects of low-level tweaks in network parameters in the LTE infrastructure on the application performance is critical to provide guidelines on how to improve the application performance in the current but also future MBB networks

  • 2.
    Fida, Mah-Rukh
    et al.
    University of Edinburgh, UK.
    Kousias, Konstantinos
    Simula Research Laboratory, Norway.
    Lutu, Andra
    Simula Research Laboratory, Norway.
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alay, Özgü
    Simula Research Laboratory, Norway.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Argyriou, Antonios
    University of Thessaly, Greece.
    Demo: experimentation in controlled and operational LTE settings with FLEX-MONROE2017In: Proceedings of the 11th Workshop on Wireless Network Testbeds, Experimental evaluation & Characterization WiNTECH '17, Association for Computing Machinery (ACM), 2017, p. 93-94Conference paper (Refereed)
    Abstract [en]

    This demo paper presents FLEX-MONROE, a platform that facilitates better understanding of current LTE Mobile Broadband(MBB) networks and enables performance improvementsby allowing experimentation with controllable LTE parameters. The platform enables investigating impact oflow-level network parameter tweaks in LTE infrastructure onthe application performance. We argue that FLEX-MONROEis crucial to provide guidelines on improving application performance both in the current and future MBB networks

  • 3.
    Grinnemo, Karl-Johan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bozakov, Zdravko
    Dell EMC.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Isabel Bueno, María
    Damjanovic, Dragana
    Mozilla.
    Rikter Evensen, Kristian
    Celerway.
    Fairhurst, Gorry
    University of Aberdeen, UK..
    Hansen, Audun
    Celerway.
    Hayes, David
    University of Oslo, Norway.
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Khademi, Naeem
    University of Oslo, Norway.
    Mangiante, Simone
    Dell EMC.
    Mohideen, Althaff
    University of Aberdeen, UK..
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ros, David
    Simula.
    Rüngeler, Irene
    FH Münster, Germany.
    Santos, Ricardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Secchi, Raffaello
    University of Aberdeen, UK..
    Christian Tangenes, Tor
    Tüxen, Micheal
    FH Münster, Germany.
    Weinrank, Felix
    FH Münster, Germany.
    Welzl, Michael
    University of Oslo, Norway.
    Deliverable D3.1 - Initial Report on the Extended Transport System2017Report (Refereed)
    Abstract [en]

    The NEAT System offers an enhanced API for applications that disentangles them from the actual transport protocol being used. The system also enables applications to communicate their service requirements to the transport system in a generic, transport-protocol independent way. Moreover, the architecture of the NEAT System promotes the evolution of new transport services. Work Package 3 (WP3) enhances and extends the core parts of the NEAT Transport. Efforts have been devoted to developing transport-protocol mechanisms that enable a wider spectrum of NEAT Transport Services, and that assist the NEAT System in facilitating several of the commercial use cases. Work has also started on the development of optimal transport-selection mechanisms; mechanisms that enable for the NEAT System to make optimal transport selections on the basis of application requirements and network measurements. Lastly, another research activity has been initiated on how to use SDN to signal application requirements to routers, switches, and similar network elements. This document provides an initial report on all these WP3 activities—both on completed and on near-termplanned work.

  • 4.
    Grinnemo, Karl-Johan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bozakov, Zdravko
    Dell EMC.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Isabel Sanchez Bueno, Maria
    Dreibholz, Thomas
    Simula.
    Rikter Evensen, Kristian
    Celerway.
    Fairhurst, Gorry
    University of Aberdeen, UK..
    Fosselie Hansen, Audun
    Celerway.
    Hayes, David
    University of Oslo, Norway.
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Jones, Tom
    University of Aberdeen, UK..
    Ros, David
    Simula.
    Rozensztrauch, Tomasz
    Celerway.
    Tüxen, Michael
    FH Münster, Germany.
    Vyncke, Eric
    CISCO.
    Deliverable D3.3 - Extended Transport System and Transparent Support of Non-NEAT Applications2017Report (Refereed)
    Abstract [en]

    This deliverable summarises and concludes our work in Work Package 3 (WP3) to extend the transport services provided by the NEAT System developed in Work Package 2, and to enable non-NEAT applications to harness the transport services offered by NEAT. We have demonstrated how a policy- and information-based selection of transport protocol by NEAT could provide a more efficient transport service for web applications. The information on which NEAT makes its transport selection decisions resides in the Characteristics Information Base (CIB). The CIB is populated by various CIB sources, and in WP3 we have designed, implemented, and evaluated various CIB sources, including meta data from mobile broadband networks, passive measurements, IPv6 Provisioning Domain protocols and the Happy Eyeballs mechanism, which caches the outcome of its connection attempts. A key property of NEAT is that it not only “vertically” decouples applications from transport protocols, but also “horizontally”. Particularly, it enables applications to harness information about resource availability and policies from Software Defined Networking (SDN) controllers in managed networks, without these applications actually being SDN-aware. To extend the use of NEAT to non-NEAT applications, we have implemented a BSDcompatible sockets API on top of NEAT and a NEAT proxy that intercepts and replaces standard TCP connections with NEAT flows, i.e., with the transport solutions deemed most appropriate by NEAT.We have also proposed a way for non-NEAT applications to make use of NEAT through the deployment of NEAT-enabled virtual appliances in SDN-controlled networks: connections from these applications are routed via an SDN-controlled proxy that terminates the original connection and replaces it with a NEAT-selected connection.

  • 5.
    Mancuso, Vincenzo
    et al.
    IMDEA Networks Institute, Spain.
    Peón Quirós, Miguel
    IMDEA Networks Institute, Spain; Ecole Polytech Fed Lausanne, Switzerland.
    Midoglu, Cise
    Simula Res Lab, Norway.
    Moulay, Mohamed
    IMDEA Networks Inst, Spain; University Carlos III of Madrid, Spain.
    Comite, Vincenzo
    IMDEA Networks Inst, Spain; University La Sapienza, Italy.
    Lutu, Andra
    Simula Res Lab, Norway.
    Alay, Ozgu
    Simula Res Lab, Norway.
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Mellia, Marco
    Politecnico di Torino, Italy.
    Khatouni, Ali Safari
    Politecnico di Torino, Italy.
    Hirsch, Thomas
    Celerway, Norway.
    Results from running an experiment as a service platform for mobile broadband networks in Europe2019In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 33, p. 89-101Article in journal (Refereed)
    Abstract [en]

    In this article we present a selection from a vast range of experiments run with MONROE, our open experiment as a service (EaaS) platform for measurements and experimentation in Mobile Broadband Networks. We show that the platform can be used to benchmark network performance in a repeatable and controlled manner thanks to the collection of a rich set of geotagged metadata and the execution of discretionary user experiments. Indeed, with the sheer amount of data collected from 12 commercial mobile operators across Europe, MONROE offers an unprecedented opportunity to monitor, analyze and ultimately improve the status of current and future mobile broadband networks. Besides, we show how flexibly the platform allows combining metadata and experimental data series during the experiments or by means of post-processing, and show results produced by our own experiments as well as comment on results obtained by external research groups and developers that have been granted access to our platform.

  • 6.
    Mohideen, Althaff C.
    et al.
    University of Aberdeen, UK.
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Secchi, Raffaello
    University of Aberdeen, UK.
    Fairhurst, Gorry
    University of Aberdeen, UK.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Weinrank, Felix
    Münster University of Applied Sciences, Germany.
    Evaluating the impact of transport mechanisms on web performance for effective web access2019In: Journal of Network and Computer Applications, ISSN 1084-8045, E-ISSN 1095-8592, Vol. 137, p. 25-34Article in journal (Refereed)
    Abstract [en]

    This paper explores the design trade-offs required for an Internet transport protocol to effectively support web access. It identifies a set of distinct transport mechanisms and explores their use with a focus on multistreaming. The mechanisms are studied using a practical methodology that utilise the range of transport features provided by TCP and SCTP. The results demonstrate the relative benefit of key transport mechanisms and analyse how these impact web access performance. Our conclusions help identify the root causes of performance impairments and suggest appropriate choices guiding the design of a web transport protocol. Performing this analysis at the level of component transport mechanisms enables the results to be utilised in the design of new transport protocols, such as IETF QUIC.

  • 7.
    Rajiullah, Mohammad
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Performance Analysis and Improvement of PR-SCTP in an Event Logging Context2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Due to certain shortcomings in TCP and UDP, the Stream Control Transmission Protocol (SCTP) was defined for transporting telephony signaling traffic. The partially reliable extension of SCTP, PR-SCTP, has been considered as a candidate for prioritizing content sensitive traffic and trading reliability against timeliness for applications with soft real time requirements. 

     

    In this thesis, we investigate the applicability of PR-SCTP for event logging applications. Event logs are inherently prioritized. This makes PR-SCTP a promising candidate for transporting event logs. However, the performance gain of PR-SCTP can be very limited when application message sizes are small and messages have mixed reliability requirements. Several factors influence PR-SCTP’s performance. One key factor is the inefficiency in the forward_tsn mechanism of PR-SCTP. We examine the inefficiency in detail and propose several solutions. Moreover, we implement and evaluate one solution that utilizes the Non-Renegable Selective Acknowledgements (NR-SACKs) mechanism currently being standardized in the IETF, which is available in the FreeBSD operating system. Our results show a significant performance gain for PR-SCTP with NR-SACKs. In some scenarios, the average message transfer delay is reduced by more than 75%. Moreover, we evaluate NR-SACK based PR-SCTP using real traces from an event logging application called syslog. It significantly improves the syslog application performance as compared to SCTP, TCP and UDP.

  • 8.
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Towards a Low Latency Internet: Understanding and Solutions2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Networking research and development have historically focused on increasing network throughput and path resource utilization, which particularly helped bulk applications such as file transfer and video streaming. Recent over-provisioning in the core of the Internet has facilitated the use of interactive applications like interactive web browsing, audio/video conferencing, multi- player online gaming and financial trading applications. Although the bulk applications rely on transferring data as fast as the network permits, interactive applications consume rather little bandwidth, depending instead on low latency. Recently, there has been an increasing concern in reducing latency in networking research, as the responsiveness of interactive applications directly influences the quality of experience.

    To appreciate the significance of latency-sensitive applications for today's Internet, we need to understand their traffic pattern and quantify their prevalence. In this thesis, we quantify the proportion of potentially latency-sensitive traffic and its development over time. Next, we show that the flow start-up mechanism in the Internet is a major source of latency for a growing proportion of traffic, as network links get faster.

    The loss recovery mechanism in the transport protocol is another major source of latency. To improve the performance of latency-sensitive applications, we propose and evaluate several modifications in TCP. We also investigate the possibility of prioritization at the transport layer to improve the loss recovery. The idea is to trade reliability for timeliness. We particularly examine the applicability of PR-SCTP with a focus on event logging. In our evaluation, the performance of PR-SCTP is largely influenced by small messages. We analyze the inefficiency in detail and propose several solutions. We particularly implement and evaluate one solution that utilizes the Non-Renegable Selective Acknowledgments (NR-SACKs) mechanism, which has been proposed for standardization in the IETF. According to the results, PR-SCTP with NR-SCAKs significantly improves the application performance in terms of low latency as compared to SCTP and TCP.

  • 9.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Evaluation and Analysis of NR-SACKs based PR-SCTP2012Conference paper (Refereed)
  • 10.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    On the Effectiveness of PR-SCTP in Networks with Competing Traffic2011In: 2011 IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATIONS (ISCC), Corfu, Greece: IEEE conference proceedings, 2011Conference paper (Refereed)
    Abstract [en]

    PR-SCTP is an extension to SCTP for partial reliability that enables a content sensitive transport service where the reliability of messages can be individually controlled. In previous work, PR-SCTP has been applied for prioritization of messages and trading of reliability against timeliness for applications such as real time video streaming, IPTV transmission, SIP signaling, and syslog. As compared to TCP, it has been shown to provide significant reductions in message transfer delay and gains in application performance. Much of the previous work has, however, considered artificial loss scenarios without competing traffic. Experiments presented in this paper show that although PR-SCTP clearly outperforms TCP in artificial loss scenarios, the performance gain is not as evident in scenarios where PR-SCTP shares a bottleneck link with competing traffic. Our analysis shows that inefficiencies in the \emph{forward\_tsn} mechanism of PR-SCTP, overhead due to small messages, and a higher loss rate per byte encountered by PR-SCTP are contributing factors to the reduced performance when network resources are shared. Finally, a proposal for a more efficient \emph{forward\_tsn} mechanism is introduced

  • 11.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Optimizing PR-SCTP Performance using NR-SACKs2012In: 2012 2nd Baltic Congress on Future Internet Communications, Vilnius: IEEE conference proceedings, 2012, p. 222-229Conference paper (Refereed)
    Abstract [en]

    A partially reliable extension of SCTP, PR-SCTP, has been considered as a candidate for prioritizing content sensitive traffic at the transport layer. PR-SCTP offers a flexible QoS trade-off between timeliness and reliability. Several applications such as streaming multimedia, IPTV transmission, and SIP signaling have been shown to benefit from this. Our previous work, however, suggests that the performance gain can be very much reduced in a network with competing traffic. One of the most important factors in this case is the inefficiency in the forward_tsn mechanism in PR-SCTP. In this paper, we thoroughly examine the forward_tsn inefficiency and propose a solution to overcome it that takes advantage of the NR-SACKs mechanism available in FreeBSD. Moreover, we implement and evaluate the proposed solution. Our initial set of results show a significant performance gain for PR-SCTP with NR-SACKs. In some scenarios the average message transfer delay is reduced by more than 75%.

  • 12.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Performance Optimization of PR-SCTP for Small Messages2011Conference paper (Other academic)
    Abstract [en]

    Stream Control Transmission Protocol (SCTP) was defined by the IETF Signaling Transport (SIGTRAN) working group to transport SS7 signaling traffic over the Internet. SCTP can also be used as a general purpose message based transport protocol. A partially reliable extension of SCTP, PR-SCTP has been considered as a candidate for prioritizing content sensitive traffic at the transport layer. By using PR-SCTP, it is possible to define various reliability policies for different application messages. An application chooses (re)transmission policy on a per message basis. A special control chunk called Forward Cumulative TSN (forward_tsn) is used to provide partial reliability. When a message is abandoned by PR-SCTP, for instance the associated lifetime is over, a forward_tsn chunk is sent to the receiver to tell it not to expect that particular message any more. PR-SCTP can offer a trade-off between timeliness and reliability for application messages when network resources become congested. Several applications such as streaming multimedia, IPTV transmission, and SIP signaling have been shown to benefit from this. Our previous work, however, suggests that the performance gain can be very limited in a network with competing traffic when message sizes are small. In this case, the most important factor is the inefficiency in the forward_tsn mechanism of PR-SCTP. In this work, we examine the forward_tsn inefficiency in detail and propose several solutions to overcome it. Moreover, we implement and evaluate one of the proposed solutions that takes advantage of the Non-Renegable Selective Acknowledgement (NR-SACK) mechanism available in the current FreeBSD OS. A receiver can use NR-SACKs to selectively acknowledge out-of-order but non-renegable data. Our results show a significant performance gain for PR-SCTP with NR-SACKs for small messages. In some scenarios the average message transfer delay is reduced by more than 75%.

  • 13.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Priority Based Delivery of PR-SCTP Messages in a Syslog Context2011In: Access networks, Springer, 2011, p. 299-310Conference paper (Refereed)
    Abstract [en]

    Unquestionably, syslog provides the most popular and easily manageable computer system logging environment. In a computer network, syslog messages are used for several purposes such as for optimizing system performance, logging user's actions and investigating malicious activities. Due to all these essential utilities, a competent transport service for syslog messages becomes important. Most of the current syslog implementations use either the unreliable UDP protocol or the more costly reliable TCP protocol. Neither of these protocols can provide both timeliness and reliability, while transporting inherently prioritized syslog messages in a congested network. In this paper, we both propose and evaluate the use of PR-SCTP, an existing partial reliability extension of the SCTP transport protocol, as a candidate transport service for the next generation syslog standard. In our emulation based experimental results, PR-SCTP shows better performance than TOP in terms of average delay for message transfer. Furthermore, PR-SCTP exhibits less average packet loss than UDP. In both cases, PR-SCTP exploits priority properties of syslog messages during loss recovery.

  • 14.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Petlund, Andreas
    Simula research lab.
    Reducing Internet Transport Latency for Thin Streams and Short Flows2013In: Future Network & Mobile Summit 2013, 2013Conference paper (Other academic)
    Abstract [en]

    The present Internet limits the performance of applications that need real- time interaction. This is in part because the design of the network has been optimised to boost throughput, maximising efficiency for bulk applications. However, changes in use have resulted in that an increasing number of applications now depend on timely delivery. One of the targets of the RITE project is to reduce internet transport latency in support of such applications. Initial results from the project on how end nodes can be optimized for more timely error recovery are presented in this poster. 

  • 15.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Petlund, Andreas
    Simula Research Laboratory.
    Welzl, Michael
    Oslo University.
    An Evaluation of Tail Loss Recovery Mechanisms for TCP2015In: Computer communication review, ISSN 0146-4833, E-ISSN 1943-5819, Vol. 45, no 1, p. 6-11Article in journal (Refereed)
    Abstract [en]

    Interactive applications do not require more bandwidth to go faster. Instead, they require less latency. Unfortunately, the current design of transport protocols such as TCP limits possible latency reductions. In this paper we evaluate and compare different loss recovery enhancements to fight tail loss latency. The two recently proposed mechanisms "RTO Restart" (RTOR) and "Tail Loss Probe" (TLP) as well as a new mechanism that applies the logic of RTOR to the TLP timer management (TLPR) are considered. The results show that the relative performance of RTOR and TLP when tail loss occurs is scenario dependent, but with TLP having potentially larger gains. The TLPR mechanism reaps the benefits of both approaches and in most scenarios it shows the best performance.

  • 16.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Lundin, Reine
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Performance Analysis and Improvement of PR-SCTP for Small Messages2013In: Computer Networks, ISSN 1389-1286, Vol. 57, no 18, p. 3967-3986Article in journal (Refereed)
    Abstract [en]

    PR-SCTP, a partially reliable extension of SCTP, provides a flexible QoS trade-off between timeliness and reliability for application traffic. However, the performance of PR-SCTP can be reduced due to certain traffic characteristics and network scenarios. Previously, we proposed a NR-SACK based optimization for PR-SCTP. In this work we extensively evaluate and analyze the performance of PR-SCTP with NR-SACKs using different network scenarios. Moreover, we compare the performance of our NR-SACK based PR-SCTP with existing transport protocols for syslog traffic. In the evaluation, we use real syslog traces from an operational syslog system. The results indicate that NR-SACKs based PR-SCTP significantly improves the overall message transfer delay as compared to SCTP and TCP.

  • 17.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Lundin, Reine
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Data Modeling and Transport of Syslog Messages2011Conference paper (Refereed)
  • 18.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Lundin, Reine
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Syslog Performance: Data Modeling and Transport2011In: Proceedings of the 3rd International Workshop on Security and Communication Networks (IWSCN 2011), Norway: IEEE Press, 2011, p. 31-37Conference paper (Refereed)
    Abstract [en]

    Syslog is one of the basic methods for event logging in computer networks. Log messages that are generated by syslog can be used for a number of purposes, including optimizing system performance, system auditing, and investigating malicious activities in a computer network. Considering all these attractive uses, both timeliness and reliability is needed when syslog messages are transported over a network. The unreliable transport protocol UDP was specified in the original syslog specification; later a reliable transport service based on TCP was also proposed. However, TCP is a costly alternative in terms of delay. In our previous work, we introduced the partially reliable extension of SCTP, PR-SCTP, as a transport service for syslog, trading reliability against timeliness by prioritizing syslog messages. In this work, we first model syslog data using real syslog traces from an operational network. The model is then used as input in the performance evaluation of PR-SCTP. In the experiments, real congestion is introduced in the network by running several competing flows. Although PR-SCTP clearly outperformed TCP and SCTP in our previous work, our present evaluations show that PR-SCTP performance is largely influenced by the syslog data size characteristics

  • 19.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lutu, Andra
    Telefonica Research, Spain.
    Ali, Safari Khatouni
    Dalhousie University, Canada.
    Fida, Mah-rukh
    Simula Metropolitan, Norway.
    Mellia, Marco
    Politecnico di Torino, Italy.
    Alay, Özgü
    Simula Metropolitan, Norway.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Mancuso, Vincenzo
    IMDEA Networks Institute, Spain.
    Web Experience in Mobile Networks: Lessons from Two Million Page Visits2019Conference paper (Refereed)
    Abstract [en]

    Measuring and characterizing web page performance is a challeng- ing task. When it comes to the mobile world, the highly varying technology characteristics coupled with the opaque network con- figuration make it even more difficult. Aiming at reproducibility, we present a large scale empirical study of web page performance collected in eleven commercial mobile networks spanning four countries. By digging into measurement from nearly two million web browsing sessions, we shed light on the impact of different web protocols, browsers, and mobile technologies on the web per- formance. We found that the impact of mobile broadband access is sizeable. For example, the median page load time using mobile broadband increases by a third compared to wired access. Mobility clearly stresses the system, with handover causing the most evi- dent performance penalties. Contrariwise, our measurements show that the adoption of HTTP/2 and QUIC has practically negligible impact. To understand the intertwining of all parameters, we adopt state-of-the-art statistical methods to identify the significance of different factors on the web performance. Our analysis confirms the importance of access technology and mobility context as well as webpage composition and browser. Our work highlights the importance of large-scale measurements. Even with our controlled setup, the complexity of the mobile web ecosystem is challenging to untangle. For this, we are releasing the dataset as open data for validation and further research.

  • 20.
    Rajiullah, Mohammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Mohideen, A. C.
    University of Aberdeen, UK.
    Weinrank, Felix
    Münster University of Applied Sciences.
    Seechi, Raffaello
    University of Aberdeen, UK.
    Fairhurst, Gorry
    University of Aberdeen, UK.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Understanding Multistreaming for Web Traffic: An Experimental Study2017In: 16th International IFIP TC6 Networking Conference, Networking 2017 / [ed] Gunnar Karlsson, Anna Brunstrom, Hongbo Jiang, Tilman Wolf, Viktoria Fodor, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    This paper explores the design trade-offs needed for an Internet transport protocol to effectively support web access over HTTP/1.1. It explores use of a multistreaming transport protocol mechanism and studies these using a practical methodology utilising the transport features of TCP and SCTP. This is used to evaluate the relative benefit of key transport mechanisms and analyse how these impact web access performance. Our conclusions help identify the root causes of performance impairments and suggest appropriate choices when selecting a suitable transport protocol.

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