Intern
    Lehrstuhl für Informatik III

    SDN - Reliabilty, Availabilty & Serviceability (SDN-RAS²)


    Researchers

    Dr. Florian Wamser,
    Christopher Metter, M.Sc.,
      Dip.-Inf. Valentin Burger

    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.

     

    Abstract:

    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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    SDN-RAS²: Kick-off

    27.07.2016

    Our new Project "SDN-RAS²" has been started today. This project focuses on Fast failure Detection in Software-Defined Networks and is a successor to our "SDN-RAS" project. We are looking forward to continue the cooperation with our partner.

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    Summary

    The need to more flexibility in the management and control of today’s networks led to the development of new networking paradigms like Software-Defined Networking (SDN) and Network Function Virtualization (NFV). The SDN paradigm introduces a more flexible control of networks by separating the network control and data plane, and logically centralizing the control plane on the so-called SDN controller. The interaction between control and data plane is typically realized by a communication using a standardized protocol like OpenFlow.

    The application of this SDN paradigm in operational networks assumes that the reliability and availability is ensured. For today’s network operators, this is one of the most important criteria when introducing SDN. To this end, therefore, sophisticated measures and innovative mechanisms are needed to ensure the required reliability and availability.

    A recent idea in this context is based the following saying: “Fail fast is more important than fail-safe”. This means, it is more important to detect errors quickly than to build a system that is 100% accurate and faultless. The latter is de-facto not possible in an operational system, which constantly changes and receives updates. For such an approach enhanced analytics of the network including its devices is a mandatory requirement as it has to be known exactly which component has failed.

    The objective of the project is to study and analyze of fast fault detection and localization techniques for SDN.


    Related publications of other projects

    • Metter, C., Seufert, M., Wamser, F., Zinner, T., Tran-Gia, P.: Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and its Application for Various Types of Traffic. IEEE Transactions on Network and Service Management. 14, 603-615 (2017).
       
    • Metter, C., Seufert, M., Wamser, F., Zinner, T., Tran-Gia, P.: Analytic Model for SDN Controller Traffic and Switch Table Occupancy. 12th International Conference on Network and Service Management (CNSM). , Best Paper Award, Montreal, Canada (2016).
       

    Student projects and theses

    • Metter, C., Seufert, M., Wamser, F., Zinner, T., Tran-Gia, P.: Analytical Model for SDN Signaling Traffic and Flow Table Occupancy and its Application for Various Types of Traffic. IEEE Transactions on Network and Service Management. 14, 603-615 (2017).
       
    • Bott, L.: Implementing Backup Paths and Recovery Strategies in an SDN controlled by ONOS, (2017).
       
    • Knapp, T.: Extending the Monitoring Features of ONOS, (2017).
       
    • Supervisor: Metter, C.: Towards OFCProbe 2.0, (2017).
       
    • Abd El Hai, S.: Measuring the Applicability of the Analytic Model for SDN Controller Traffic and Switch Table Occupancy, (2017).
       
    • Knapp, T.: Assessment of the ONOS SDN Controller in Case of Network Errors, (2016).
       
    • Rachor, C.: Testbed-based RAS Evaluation in SDN using ONOS, (2015).
       
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