Gate Control List Research Articles

An Efficient Time‐Sensitive Networking Traffic Scheduling Method for Train Communication Network

As a critical system of rail train, the train communication network (TCN) is an integrated central platform that is used to realize the train operation control, condition monitoring, and data transmission. With the development of train intelligence, the scale of data flow in TCN continues to expand, and the control data and monitoring data must be real‐time transmitted to ensure the safe and reliable operation of the train. Time‐sensitive network (TSN) can be applied as the next‐generation TCN solution, which provides end‐to‐end data transmission with extremely low delay and high reliability based on Ethernet. For the application of TSN technology in TCN, a single frame simple scheduling method is proposed to effectively reduce the worst end‐to‐end delay of the entire network, which improve the real‐time performance of TSN‐based TCN. The network topology and data flow characteristics in TCN are analyzed, a series of scheduling constraints are constructed, and the satisfiability modulo theories (SMT) is used to obtain a gate control list (GCL) to ensure the real‐time performance of time‐trigger streams. Finally, the TCN simulation model is established using OMnet++ software, the experiment results show that the proposed method can effectively reduce the overall delay and jitter, and meet the real‐time requirement of TCN. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Configuration of multi‐shaper Time‐Sensitive Networking for industrial applications

AbstractIEEE 802.1 Time‐Sensitive Networking (TSN) has proposed several shapers, for example, time‐aware shaper (TAS, 802.1Qbv), asynchronous traffic shaping (ATS, 802.1Qcr), credit‐based shaper (CBS, 802.1Qav), and cyclic queuing and forwarding (CQF, 802.1Qch). The shapers have their advantages and disadvantages and can be used in isolation or in combination to address the varied timing requirements of industrial application streams. There is very limited work on how to analyse and configure shaper combinations. The authors are interested in the configuration optimisation of multi‐shaper TSN networks, targeting the TAS + CBS, TAS + ATS, and TAS + Multi‐CQF combinations. The authors first propose multi‐shaper integration approaches, focusing on a novel iterative delay analysis for TAS + ATS, an approach to integrate TAS and CQF by placing constraints on TAS scheduling as well as the TAS and CBS integration. We formulate the combinatorial optimisation problem of configuring multi‐shaper TSN networks, which consists, for example, of the routing of streams, the assignment of streams to the egress port queues, and the synthesis of gate control lists for TAS. Then, the authors propose a solution based on a simulated annealing metaheuristic. The proposed solutions are evaluated on large realistic test cases, up to tens of thousands of streams and devices.

Enhanced Real-time Scheduling of AVB Flows in Time-Sensitive Networking

Time-Sensitive Networking (TSN) realizes high bandwidth and time determinism for data transmission and thus becomes the crucial communication technology in time-critical systems. The Gate Control List (GCL) is used to control the transmission of different classes of traffic in TSN, including Time-Triggered (TT) flows, Audio-Video-Bridging (AVB) flows, and Best-Effort (BE) flows. Most studies focus on optimizing GCL synthesis by reserving the preceding time slots to serve TT flows with the strict delay requirement, but ignore the deadlines of non-TT flows and cause the large delay. Therefore, this paper proposes a comprehensive scheduling method to enhance the real-time scheduling of AVB flows while guaranteeing the time determinism of TT flows. This method first optimizes GCL synthesis to reserve the preceding time slots for AVB flows, and then introduces the Earliest Deadline First (EDF) method to further improve the transmission of AVB flows by considering their deadlines. Moreover, the worst-case delay (WCD) analysis method is proposed to verify the effectiveness of the proposed method. Experimental results show that the proposed method improves the transmission of AVB flows compared to the state-of-the-art methods.

Scheduling Time-Critical Traffic With Virtual Queues in Software-Defined Time-Sensitive Networking

The emerging applications in vertical industries generate diverse time-critical traffic flows with bounded delay requirements. Time-Sensitive Networking (TSN) enhances the traditional Ethernet by using Time-Aware Shaper (TAS), providing delay guarantees for traffic flow transmission. However, the fixed scheduling granularity of physical queues in TAS can bring an obstacle for the flow isolation in per-flow scheduling, such as the complex computing and configuration. This paper proposes a method of Virtual Queues-based Time-Aware Traffic Scheduling (VQ-TATS) in Software-Defined Time-Sensitive Networking (SD-TSN). SD-TSN is a networking architecture that integrates the determinism guarantees of TSN and flexible network resource allocation of Software-Defined Networking (SDN). Through the capability of SD-TSN, the physical queues resource is virtualized for VQ-TATS. VQ-TATS includes the VQ clustering and VQ mapping stages. VQ clustering aggerates virtual queues to adapt to the scheduling granularity of TAS. VQ mapping builds the relationship between virtual and physical queues and generates the gate control list of TAS. The clustering and mapping algorithms are also designed to perform VQ-TATS. The evaluation in an industrial control use case shows the effectiveness of the proposed method in schedulability and runtime.

Deep Reinforcement Learning-Based Joint Scheduling of 5G and TSN in Industrial Networks

5th-Generation (5G) and Time-Sensitive Networking (TSN) are regarded as competitive new technologies for future industrial networks; 5G-TSN collaboration transmission has drawn more attention because it can provide a guarantee of low-latency, ultra-reliable and deterministic transmission for time-critical automation applications. However, the methodologies of resource scheduling mechanisms in 5G and Time-Sensitive Networking (TSN) are quite different, which may lead to an inefficient Quality of Service (QoS) guarantee for deterministic transmission across 5G and TSN. Therefore, an efficient 5G-TSN joint scheduling algorithm based on Deep Deterministic Policy Gradient (DDPG) is proposed and analyzed in this article. The proposed algorithm takes both 5G radio channel information and the Gate Control List (GCL) state in the TSN domain into consideration, aiming to provide a latency guarantee for time-triggered applications across 5G and TSN as well as a throughput guarantee for video applications in 5G systems. The simulation results compare the latency and throughput performance of the proposed joint scheduling algorithm with several traditional 5G scheduling algorithms; meanwhile, several GCL setting methods are given to verify the impacts on latency and throughput performance within the proposed algorithm. The simulation results demonstrate that the proposed DDPG-based joint scheduling algorithm can significantly enhance the multi-application-carrying capability of 5G-TSN collaboration architecture.

A unified flow scheduling method for time sensitive networks

Given the network and the time-triggered flow requests of a Time Sensitive Network (TSN), configuring the gate control lists (GCL) of IEEE 802.1Qbv for the ports of each node can be formed as a Job Shop Scheduling Problem, which is NP-hard. At present, most of the existing heuristic solutions for such problems consider scenarios where all given traffic flows can be scheduled. In order to solve the undetermined flow scheduling problem in scenarios no matter whether the flows can be scheduled or not, we propose to maximize the remaining time in conjunction with optimizing the network utilization instead of only minimizing the flowspan. Though the new problem is still NP-hard, it is a unified framework capable of covering general scenarios. On the basis of the new framework, we propose a novel Mixed initial population Genetic Algorithm (MGA) to solve the problem. Extensive simulation evaluation shows that MGA performs better and faster in different network scenarios while other methods prevails only in specific scenarios. This feature makes the method attractive in realistic TSN scheduling applications for in most cases it is hard for users to properly classifying the problem.

A Max-Min Scheduling Algorithm Based on TAS Mechanism

In order to solve the problem of too many guard bands and gate control lists (GCL) caused by time triggered (TT) flow scheduling per flow, this paper proposes a maximum minimum cycle scheduling algorithm based on time aware shaping (TAS) mechanism. At the same time, a period shift algorithm is proposed to overcome the excessive super period of TT flow. The results show that compared with the conventional scheduling methods, this method can ensure the deterministic transmission requirements of TT flows, and reduce the number of protection bands and GCLs.

ReTSN: Resilient and Efficient Time-Sensitive Network for Automotive In-Vehicle Communication

Time-sensitive networking (TSN) is being widely investigated to provide Ethernet capabilities for in-vehicle backbone communication. However, the gate control list (GCL), as a simple mechanism for achieving timing determinism for safety-critical traffic (ST) frames with hard deadlines, is too rigid to handle the intrinsic timing uncertainty of automated driving systems (ADSs). Due to the complexity and the unpredictable operating environment, there can be delayed ST frames that can disrupt the solidly fixed timing behavior. In this work, we present one novel approach to effectively use bandwidth resources to deal with delayed ST frames, which cannot be handled by a traditional fixed GCL, and the discarding of them should be reduced to improve the system’s integrity. An acceptance test is implemented to report to the application layer when an ST frame will miss its deadline and hence be rejected, i.e., prevented from entering the switch. To further improve the efficiency of bandwidth usage, we investigate how to improve the performance of the more important Class A frames in an audio-video-bridging (AVB) switch, which adopts a credit-based shaper mechanism, and we propose a constant bandwidth server to replace the credit-based shaper while taking fairness into consideration. Evaluation with extensive experiments shows that both resilience and efficiency of the TSN are significantly enhanced compared with a credit-based shaper, especially when the traffic load is relatively high. For the delayed ST frames and event-triggered traffic, our approach is able to schedule more than the solution using the AVB switch even with a high network load.

Optimization of Bandwidth Utilization and Gate Control List Configuration in 802.1Qbv Networks

Optimization of Bandwidth Utilization and Gate Control List Configuration in 802.1Qbv Networks

Adaptive Priority Adjustment Scheduling Approach With Response-Time Analysis in Time-Sensitive Networks

With the advent of Industry 4.0 and the popularization of smart terminal equipment, the interaction between industrial field information systems and production equipment has intensified. To meet the real-time transmission of time-triggered flow and the coordinated transmission of best effort flow, time-sensitive network-related technologies are used to implement flow queue forwarding by strictly following the gate control list. First, response-time analysis method is proposed to predict the upper bound of delay under a scheduling model following IEEE 802.1Qbv. Second, according to response-time analysis, a deadline monotonic scheduling algorithm with temporary priority expansion is proposed to divide the priority into more levels, which is not limited by the queue type, so as to ameliorate the transmission sequence of switch export flow. Finally, an adaptive priority adjustment scheduling algorithm with temporary priority expansion is designed to construct the optimal scheduling method further improving the scheduling success rate and reducing worst-case end-to-end delays. Compared with similar algorithms, the algorithm proposed improves the scheduling success rate by at least 30%, reduces the total delay by at least 21% and the TT flow delay by 11% in high network utilization conditions.

Dependability‐aware routing and scheduling for Time‐Sensitive Networking

Time-Sensitive Networking (TSN) extends IEEE 802.1 Ethernet for safety-critical and real-time applications in several areas, for example, automotive, aerospace or industrial automation. However, many of these systems also have stringent security requirements, and security attacks may impair safety. Given a TSN-based distributed architecture, a set of applications with tasks and messages as well as a set of security and redundancy requirements, the authors are interested to synthesise a system configuration such that the real-time, safety and security requirements are upheld. The Timed Efficient Stream Loss-Tolerant Authentication (TESLA) low-resource multicast authentication protocol is used to guarantee the security requirements and redundant disjunct message routes to tolerate link failures. The authors consider that tasks are dispatched using a static cyclic schedule table and that the messages use the time-sensitive traffic class in TSN, which relies on schedule tables (called Gate Control Lists, GCLs) in the network switches. A configuration consists of the schedule tables for tasks as well as the disjoint routes and GCLs for messages. A Constraint Programing-based formulation, which can be used to find an optimal solution with respect to the cost function, is proposed. Additionally, a Simulated Annealing-based metaheuristic, which can find good solution for large test cases, is proposed. The authors evaluate both approaches on several test cases.

Configuring ADAS Platforms for Automotive Applications Using Metaheuristics.

Modern Advanced Driver-Assistance Systems (ADAS) combine critical real-time and non-critical best-effort tasks and messages onto an integrated multi-core multi-SoC hardware platform. The real-time safety-critical software tasks have complex interdependencies in the form of end-to-end latency chains featuring, e.g., sensing, processing/sensor fusion, and actuating. The underlying real-time operating systems running on top of the multi-core platform use static cyclic scheduling for the software tasks, while the communication backbone is either realized through PCIe or Time-Sensitive Networking (TSN). In this paper, we address the problem of configuring ADAS platforms for automotive applications, which means deciding the mapping of tasks to processing cores and the scheduling of tasks and messages. Time-critical messages are transmitted in a scheduled manner via the timed-gate mechanism described in IEEE 802.1Qbv according to the pre-computed Gate Control List (GCL) schedule. We study the computation of the assignment of tasks to the available platform CPUs/cores, the static schedule tables for the real-time tasks, as well as the GCLs, such that task and message deadlines, as well as end-to-end task chain latencies, are satisfied. This is an intractable combinatorial optimization problem. As the ADAS platforms and applications become increasingly complex, such problems cannot be optimally solved and require problem-specific heuristics or metaheuristics to determine good quality feasible solutions in a reasonable time. We propose two metaheuristic solutions, a Genetic Algorithm (GA) and one based on Simulated Annealing (SA), both creating static schedule tables for tasks by simulating Earliest Deadline First (EDF) dispatching with different task deadlines and offsets. Furthermore, we use a List Scheduling-based heuristic to create the GCLs in platforms featuring a TSN backbone. We evaluate the proposed solution with real-world and synthetic test cases scaled to fit the future requirements of ADAS systems. The results show that our heuristic strategy can find correct solutions that meet the complex timing and dependency constraints at a higher rate than the related work approaches, i.e., the jitter constraints are satisfied in over 6 times more cases, and the task chain constraints are satisfied in 41% more cases on average. Our method scales well with the growing trend of ADAS platforms.

Design of coordinated transmission mechanism of heterogeneoustime-sensitive data flow for industrial internet

<p indent="0mm">Industrial internet needs to realize the integration of IT (information technology) and OT (operation technology). The construction of the field-level industrial network is key to truly realizing seamless access of production line data from OT to IT and the intelligent operation and maintenance of the production line from IT to OT. For OT, the data in the industrial system is highly time-sensitive, and the deterministic behavior of perceived data and control instructions in time is the foundation for reliable and stable industrial system operation. However, the industrial field is plagued by problems such as heterogeneous perceived data, incompatible protocols, and varying transmission requirements, which pose significant challenges to the deterministic transmission of heterogeneous time-sensitive flow. One feasible solution to this problem is to design a unified time-aware gating mechanism with low delay and jitter, allowing precise control of data flow transmission behavior; this is one of the key technologies in the time-sensitive networking (TSN) standard. This paper mainly studies the coordinated transmission of heterogeneous time-sensitive flow in multi-hop TSN networks. First, heterogeneous time-sensitive traffic is modeled into two categories: periodic time-sensitive (PTS) flow and sporadic time-sensitive (STS) flow. Then, the schedulability of the PTS flow set and the design method of the gate control lists are analyzed, the sufficient and necessary conditions of schedulability are defined, and a schedulability discriminant algorithm is designed to determine the schedulability of any decision set. Then, a coordinated transmission framework of heterogeneous time-sensitive flow is proposed, followed by the construction of the constraint set of heterogeneous data scheduling. This paper employs the design method of no-wait slot scheduling and constructs the heterogeneous time-sensitive flow scheduling problem with the optimization goal of minimizing the maximum slot occupation in the scheduling unit to achieve the minimum end-to-end deterministic delay of PTS flow and to reduce the impact of PTS scheduling mechanism on STS flow transmission as much as possible. Then, a uniform arrangement and filling (UAF) algorithm is developed to minimize slot occupation of scheduling units by uniformly arranging the flow of the same period and filling the idle time slots generated during pre-period scheduling. Finally, simulation and experiment results corroborate the effectiveness of the two kinds of heterogeneous time-sensitive flow coordinated transmission framework and the efficiency of the UAF scheduling algorithm based on ensuring the same scheduling performance.

Latency Analysis of Multiple Classes of AVB Traffic in TSN With Standard Credit Behavior Using Network Calculus

Time-sensitive networking (TSN) is a set of amendments that extend Ethernet to support distributed safety-critical and real-time applications in the industrial automation, aerospace, and automotive areas. TSN integrates multiple traffic types and supports interactions in several combinations. In this article, we consider the configuration supporting scheduled traffic (ST) based on gate-control lists, audio–video bridging (AVB) traffic according to IEEE 802.1BA that has bounded latencies, and best-effort traffic, for which no guarantees are provided. This article extends the timing analysis method to multiple AVB classes and proofs the credit bounds for multiple classes of AVB traffic, respectively, under frozen and nonfrozen behaviors of credit during guard band (GB). They are prerequisites for nonoverflow credits of credit-based shaper (CBS) and preventing starvation of AVB traffic. Moreover, this article proposes an improved timing analysis method reducing the pessimism for the worst-case end-to-end delays of AVB traffic by considering the limitations from the physical link rate and the output of CBS. Finally, we evaluate the improved analysis method on both synthetic and real-world test cases, showing the significant reduction of pessimism on latency bounds compared to related work and presenting the correctness validation compared with simulation results. We also compare the AVB latency bounds in the case of frozen and nonfrozen credit during GB. Additionally, we evaluate the scalability of our method with variation of the load of ST flows and of the bandwidth reservation for AVB traffic.

Research on Gating Scheduling of Time Sensitive Network Based on Constraint Strategy

With the continuous development of industry, information and intelligence have gradually become the keywords of industrial control. In modern industrial scenarios, more and more devices are connected to the factory network, and the complex network environment will greatly affect the end-to-end transmission performance of key control flows, which brings a huge impact to those high-precision control signal transmissions. With the development of Time Sensitive Network (TSN) in recent years, more and more people have introduced this technology to the field of industrial control. In this paper, we propose a scheduling scheme based on constraint strategy for the key technology of TSN—Time Aware Shaper (TAS). This scheme can derive the appropriate network constraint strategy and optimization scheme of network resource utilization according to the end-to-end Quality of Service (QoS) of multiple key data streams in the network, and finally obtain the configuration scheme of Gate Control Lists (GCLs).

Reconfiguration algorithms for high precision communications in time sensitive networks: Time-aware shaper configuration with IEEE 802.1Qcc

As new networking paradigms emerge for different networking applications, e.g., cyber-physical systems, and different services are handled under a converged data link technology, e.g., Ethernet, certain applications with mission critical traffic cannot coexist on the same physical networking infrastructure using traditional Ethernet packet-switched networking protocols. The IEEE 802.1Q Time Sensitive Networking (TSN) Task Group is developing protocol standards to provide deterministic properties, i.e., eliminates non-deterministic delays, on Ethernet based packet-switched networks. In particular, the IEEE 802.1Qcc, centralized management and control, and the IEEE 802.1Qbv, Time-Aware Shaper (TAS), can be used to manage and control Scheduled Traffic (ST) streams with periodic properties along with Best-Effort (BE) traffic on the same network infrastructure. We investigate the effects of using the IEEE 802.1Qcc management protocol to accurately and precisely configure TAS enabled switches (with transmission windows governed by Gate Control Lists (GCLs) with Gate Control Entries (GCEs)) ensuring ultra-low bounded latency, zero packet loss, and minimal jitter for ST TSN traffic. We examine both a centralized network/distributed user model (hybrid model) and a fully-distributed (decentralized) 802.1Qcc model on a typical industrial control network with the goal of maximizing the number of ST streams.

Queue scheduling mechanism of integrative intelligent network based on information age

Aiming at the problems of deterministic transmission of delay-sensitive service flows and mixed transmission of different service flows in the integrative intelligent network, which can easily lead to network congestion collapse and excessive delay, a scheduling mechanism named SATAS based on information age is proposed. The service flows in the intelligent network aggregation node are classified into delay-sensitive and other types of service flows. Based on the idea of time division multiplexing, the service flow in the buffer queue is scheduled according to the gated list. Further, combined with the age of information, based on the multi-objective optimization decision-making theory, and according to the actual requirements of scheduling in the intelligent network, a suitable gate control list is obtained, thereby realizing the scheduling of business flows in the intelligent network. Finally, a simulation verification system is built to schedule different types of business flows. The simulation results show that the SATAS mechanism ensures the deterministic transmission of delay-sensitive service flows, while ensuring the mixed transmission of different service flows, reducing the queuing delay and frame loss rate.

Real-Time Reconfiguration of Time-Aware Shaper for ULL Transmission in Dynamic Conditions

Many applications such as Industrial Internet of Things (IIoT), tactile Internet, and 5G/6G mobile require Ultra-Low Latency (ULL) in data transmission. The end-to-end latency is required to be on the order of sub-millisecond in these applications. The IEEE 802.1 Time Sensitive Networking (TSN) standards have been developed to provide ULL networking. The IEEE 802.1Qbv Time-Aware Shaper (TAS), which is a typical flow control mechanism of TSN, is a traffic shaper to provide deterministic end-to-end ULL transmission for express traffic. The Gate Control List (GCL) of all TAS enabled nodes must be configured in a coordinated manner to ensure ULL. However, existing configuration schemes cannot be employed in highly dynamic conditions where the distribution of time-sensitive streams frequently changes. It will be a significant problem to deal with such dynamic conditions in the future. Therefore, this paper proposes a real-time adaptive gate scheduling scheme for TAS. The scheduling problem is formulated as a boolean satisfiability problem (SAT), and the employment of an FPGA-based solver is proposed to achieve runtime fast computation. The proposed scheme enables real-time reconfiguration for high flexibility and high bandwidth utilization to deal with the dynamics of network conditions. The feasibility of the proposed scheme is confirmed with computer simulations.

Communication Scheduling for Control Performance in TSN-Based Fog Computing Platforms

In this paper we are interested in real-time control applications that are implemented using Fog Computing Platforms consisting of interconnected heterogeneous Fog Nodes (FNs). Similar to previous research and ongoing standardization efforts, we assume that the communication between FNs is achieved via the IEEE 802.1 Time Sensitive Networking (TSN) standard. We model the control applications as a set of real-time flows, and we assume that the messages are transmitted using scheduled traffic that is using the Gate Control Lists (GCLs) in TSN. Given a network topology and a set of control applications, we are interested to synthesize the GCLs for messages such that the Quality-of-Control (QoC) of control applications is maximized and the deadlines of real-time messages are satisfied. We have proposed a Constraint Programming (CP)-based solution to this problem, and developed an accurate analytical model for QoC, which, together with a metaheuristic search employed in the CP solver can drive the search quickly towards good quality solutions. We have evaluated the proposed strategy on several test cases including realistic test cases and also validate the resulted GCLs on a TSN hardware platform and via simulations in OMNET++.

Critical Offset Optimizations for Overlapping-Based Time-Triggered Windows in Time-Sensitive Network

Deterministic and low latency communications are increasingly becoming essential requirements for several safety-critical applications, such as automotive and automation industries. Time-sensitive networking (TSN) is an element of the new IEEE 802.1 standards that introduced Ethernet-based amendments to support these applications. One of these enhancements was presented in IEEE 802.1Qbv to define the time-aware shaping (TAS) technique for time-triggered (TT) traffic scheduling. The TAS mechanism is window-based scheduling using a gating system controlled by the gate control list (GCL) schedules in all nodes. Although several scheduling algorithms have been proposed to investigate the effects of window-related parameters on network performance, the offset difference ( $OD$ ) between the same-class windows in the adjoining nodes has not been optimized yet. These optimizations are extremely crucial to implement less pessimistic latency schedules. This paper proposes an optimized flexible window-overlapping scheduling (OFWOS) algorithm that optimizes TT window offsets based on latency evaluations considering the overlapping between different priority windows at the same node. First, we formulate the GCL timings as mathematical forms under variable $OD\text{s}$ between the same-priority windows. Then, an analytical model is implemented using the network calculus (NC) approach to express the worst-case end-to-end delay ( $WCD$ ) for TT flows and evaluated using a realistic vehicular use case. The OFWOS model optimizes $OD$ under all overlapping situations between TT windows at the same node. Compared with the latest works of 3-hop and 30-hop TSN connections, the OFWOS reduces the $WCD$ bounds by 8.4% and 32.6%, respectively, accomplishing less pessimistic end-to-end latency bounds.