1,278 research outputs found
Simulation of Mixed Critical In-vehicular Networks
Future automotive applications ranging from advanced driver assistance to
autonomous driving will largely increase demands on in-vehicular networks. Data
flows of high bandwidth or low latency requirements, but in particular many
additional communication relations will introduce a new level of complexity to
the in-car communication system. It is expected that future communication
backbones which interconnect sensors and actuators with ECU in cars will be
built on Ethernet technologies. However, signalling from different application
domains demands for network services of tailored attributes, including
real-time transmission protocols as defined in the TSN Ethernet extensions.
These QoS constraints will increase network complexity even further.
Event-based simulation is a key technology to master the challenges of an
in-car network design. This chapter introduces the domain-specific aspects and
simulation models for in-vehicular networks and presents an overview of the
car-centric network design process. Starting from a domain specific description
language, we cover the corresponding simulation models with their workflows and
apply our approach to a related case study for an in-car network of a premium
car
Development of Algorithm for Calculating Data Packet Transmission Delay in Software-Defined Networks
The relevance of this type of network is associated with the development and improvement of protocols, methods, and tools to verify routing policies and algorithmic models describing various aspects of SDN, which determined the purpose of this study. The main purpose of this work is to develop specialized methods to estimate the maximum end-to-end delay during packet transmission using SDN infrastructure. The methods of network calculus theory are used to build a model for estimating the maximum transmission delay of a data packet. The basis for this theory is obtaining deterministic evaluations by analyzing the best and worst-case scenarios for individual parts of the network and then optimally combining the best ones. It was found that the developed method of theoretical evaluation demonstrates high accuracy. Consequently, it is shown that the developed algorithm can estimate SND performance. It is possible to conclude the configuration optimality of elements in the network by comparing the different possible configurations. Furthermore, the proposed algorithm for calculating the upper estimate for packet transmission delay can reduce network maintenance costs by detecting inconsistencies between network equipment settings and requirements. The scientific novelty of these results is that it became possible to calculate the achievable upper data delay in polynomial time even in the case of arbitrary tree topologies, but not only when the network handlers are located in tandem. Doi: 10.28991/ESJ-2022-06-05-010 Full Text: PD
Small is Beautiful: Scaling Down the Long Center for the Performing Arts in Austin
This case was prepared for a class discussion rather than to demonstrate either effective or ineffective handling of an administrative situation, and is based on seven interviews with staff, board members, and community leaders involved with the Long Center for the Performing Arts project as well as internal documents and the public record. The authors would like to thank all of the people who graciously agreed to be interviewed
Real-Time Scheduling for Time-Sensitive Networking: A Systematic Review and Experimental Study
Time-Sensitive Networking (TSN) has been recognized as one of the key
enabling technologies for Industry 4.0 and has been deployed in many time- and
mission-critical industrial applications, e.g., automotive and aerospace
systems. Given the stringent real-time communication requirements raised by
these applications, the Time-Aware Shaper (TAS) draws special attention among
the many traffic shapers developed for TSN, due to its ability to achieve
deterministic latency guarantees. Extensive efforts on the designs of
scheduling methods for TAS shapers have been reported in recent years to
improve the system schedulability, each with their own distinct focuses and
concerns. However, these scheduling methods have yet to be thoroughly
evaluated, especially through experimental comparisons, to provide a
systematical understanding on their performance using different evaluation
metrics in various application scenarios. In this paper, we fill this gap by
presenting a comprehensive experimental study on the existing TAS-based
scheduling methods for TSN. We first categorize the system models employed in
these work along with their formulated problems, and outline the fundamental
considerations in the designs of TAS-based scheduling methods. We then perform
extensive evaluation on 16 representative solutions and compare their
performance under both synthetic scenarios and real-life industrial use cases.
Through these experimental studies, we identify the limitations of individual
scheduling methods and highlight several important findings. This work will
provide foundational knowledge for the future studies on TSN real-time
scheduling problems, and serve as the performance benchmarking for scheduling
method development in TSN.Comment: 22 pages, ac
Just a Second -- Scheduling Thousands of Time-Triggered Streams in Large-Scale Networks
Deterministic real-time communication with bounded delay is an essential
requirement for many safety-critical cyber-physical systems, and has received
much attention from major standardization bodies such as IEEE and IETF. In
particular, Ethernet technology has been extended by time-triggered scheduling
mechanisms in standards like TTEthernet and Time-Sensitive Networking. Although
the scheduling mechanisms have become part of standards, the traffic planning
algorithms to create time-triggered schedules are still an open and challenging
research question due to the problem's high complexity. In particular,
so-called plug-and-produce scenarios require the ability to extend schedules on
the fly within seconds. The need for scalable scheduling and routing algorithms
is further supported by large-scale distributed real-time systems like smart
energy grids with tight communication requirements. In this paper, we tackle
this challenge by proposing two novel algorithms called Hierarchical Heuristic
Scheduling (H2S) and Cost-Efficient Lazy Forwarding Scheduling (CELF) to
calculate time-triggered schedules for TTEthernet. H2S and CELF are highly
efficient and scalable, calculating schedules for more than 45,000 streams on
random networks with 1,000 bridges as well as a realistic energy grid network
within sub-seconds to seconds
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