Design of a Networked Controller for a Two-Wheeled Inverted Pendulum Robot

The topic of this paper is to use an intuitive model-based approach to design a networked controller for a recent benchmark scenario. The benchmark problem is to remotely control a two-wheeled inverted pendulum robot via W-LAN communication. The robot has to keep a vertical upright position. Incorporating wireless communication in the control loop introduces multiple uncertainties and affects system performance and stability. The proposed networked control scheme employs model predictive techniques and deliberately extends delays in order to make them constant and deterministic. The performance of the resulting networked control system is evaluated experimentally with a predefined benchmarking experiment and is compared to local control involving no delays.Comment: Submitted to IFAC Necsys 201

MoonGen: A Scriptable High-Speed Packet Generator

We present MoonGen, a flexible high-speed packet generator. It can saturate 10 GbE links with minimum sized packets using only a single CPU core by running on top of the packet processing framework DPDK. Linear multi-core scaling allows for even higher rates: We have tested MoonGen with up to 178.5 Mpps at 120 Gbit/s. We move the whole packet generation logic into user-controlled Lua scripts to achieve the highest possible flexibility. In addition, we utilize hardware features of Intel NICs that have not been used for packet generators previously. A key feature is the measurement of latency with sub-microsecond precision and accuracy by using hardware timestamping capabilities of modern commodity NICs. We address timing issues with software-based packet generators and apply methods to mitigate them with both hardware support on commodity NICs and with a novel method to control the inter-packet gap in software. Features that were previously only possible with hardware-based solutions are now provided by MoonGen on commodity hardware. MoonGen is available as free software under the MIT license at https://github.com/emmericp/MoonGenComment: Published at IMC 201

Never Miss Twice - Add-On-Miss Table Updates in Software Data Planes

State Management at line rate is crucial for critical applications in next-generation networks. P4 is a language used in software-defined networking to program the data plane. The data plane can profit in many circumstances when it is allowed to manage its state without any detour over a controller. This work is based on a previous study by investigating the potential and performance of add-on-miss insertions of state by the data plane. The state keeping capabilities of P4 are limited regarding the amount of data and the update frequency. We follow the tentative specification of an upcoming portable-NIC-architecture and implement these changes into the software P4 target T4P4S. We show that insertions are possible with only a slight overhead compared to lookups and evaluate the influence of the rate of insertions on their latency

Reproducible by Design: Network Experiments with pos

In scientific research, the independent reproduction of experiments is the source of trust. Detailed documentation is required to enable experiment reproduction. Reproducibility awards were created to honor the increased documentation effort. In this work, we propose a novel approach toward reproducible research—a structured experimental workflow that allows the creation of reproducible experiments without requiring additional efforts of the researcher. Moreover, we present our own testbed and toolchain, namely, plain orchestrating service (pos), which enables the creation of such experimental workflows. The experiment is documented by our proposed, fully scripted experiment structure. In addition, pos provides scripts enabling the automation of the bundling and release of all experimental artifacts. We provide an interactive environment where pos experiments can be executed and reproduced, available at https://gallenmu.github.io/single-server-experiment

Experimental Research Reproducibility and Experiment Workflow Management

Research reproducibility is an important factor to support the full research life cycle; this is especially important for experimental research, where it is required to also reproduce the whole experiment environment and equipment setup. This paper presents the methodology and solution proposed in the SLICES Research Infrastructure to enable research reproducibility in modern digital technologies for complex and large scale experimentation. The paper provides a short overview of existing research and approaches for experimental research reproducibility, generally including git based experiments deployment and operation, Jupyter Notebook and Common Workflow Language (CWL) for workflow management. The paper describes the framework and approaches taken in the SLICES-RI that also address research environment provisioning on demand with the Platform Research Infrastructure as a Service (PRIaaS) and data management infrastructure to ensure data quality and support effective data sharing