Lehrstuhl für Informatik III

    Working Group: Cloud Applications and Networks

    We do research in the field of contemporary cloud architectures and communication networks.
    Of particular interest are the applications and services that are to be used on the network. Fundamental issues center around dynamic and adaptive networks as well as cloud architectures and principles, which play an increasingly important role in today's networks.    » more

    Head Dr. Florian Wamser

    Valentin Burger 

    Christopher Metter

    Michael Seufert

    Lam Dinh-Xuan

    Frank Loh

    Anika Schwind

    Student Tutors

    Bernd Zeidler

    Markus Meixner

    Nikolas Wehner

    Simon Englert

    Lea Janiak

    Philipp Waigand

    The workshop "Internet QoE" was successfully completed in Los Angeles @ UCLA. Four keynotes were given, a panel discussion was held, and 7 full papers were presented. Slides of the keynotes are available on request at <>.


    ACM SIGCOMM 2017 2nd Workshop on QoE-based Analysis and Management of Data Communication Networks (Internet-QoE 2017)


    An extended version of our paper "Analytic Model for SDN Controller Traffic and Switch Table Occupancy" will be published in the next issue of the IEEE Transactions on Network and Service Management.



    Software Defined Networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks. The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switch and the controller. Based on this traffic, rules are created in the flow table of the switch, which specify the forwarding behavior. To avoid table overflows, unused entries are removed after a predefined time-out period. Given a specific traffic mix, the choice of this time-out period affects the trade-off between signaling rate and table occupancy. As a result, network operators have to adjust this parameter to enable a smooth and efficient network operation. Due to the complexity of this problem caused by the various traffic flows in a network, a suitable abstraction is necessary in order to derive valid parameter values in time. The contribution of this work is threefold. Firstly, we formulate a simple analytical model that allows optimizing the network performance with respect to the table occupancy and the signaling rate. Secondly, we validate the model by means of simulation. Thirdly, we illustrate the impact of the time-out period on the signaling traffic and the flow table occupancy for different data-plane traffic mixes and characteristics. This includes scenarios with single application instances, as well as multiple application instances of different application types in an SDN-enabled network.

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    Scientific Focus

    The figure places the various work and research topics to the axes with respect to the terms cloud, network and applications.





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    Lehrstuhl für Informatik III (Kommunikationsnetze)
    Am Hubland
    97074 Würzburg

    Tel.: +49 931 31-86631

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    Hubland Süd, Geb. M2