|
|
|
|
| Bachelorprojekt - Softwareteknologi | Project No. 0217: Comparison of traffic classes for Time-Sensitive Networking |
| Aktuelle | Tidligere |
There is the communication protocol colloquially known as Time-Sensitive Networking (TSN )[1] that is used in several application areas, from industrial automation to automotive architectures. For example, in the automotive area, fault-tolerant TSN networks are envisioned in future autonomous driving architectures, since they have the bandwidth requirements to integrate traffic from multiple sensors and the dependability required for autonomous driving.
TSN [1] is a set of sub-standards which extend the IEEE 802.1 standards (for switched Ethernet networks) for safety-critical and real-time applications. First, IEEE 802.1Q-2005 introduced support for prioritizing the Best-Effort (BE) traffic in order to improve Quality of Services (QoSs). Following this, the IEEE Audio-Video-Bridging (AVB) Task Group was formed to develop another set of enhancements, namely IEEE 802.1BA known as AVB. This standard introduces two new shaped AVB traffic-types, with bounded Worst-Case end-to-end Delays (WCDs). In 2012, the AVB Task Group was renamed to IEEE 802.1 Time-Sensitive Networking Task Group to reflect the shifted focus onto further extending the protocol towards safety-critical and time-sensitive transmissions, and has introduced new traffic types such as Time-Triggered (TT) [2] and Asynchronous Traffic Shaping (ATS) [3].
TT traffic supports hard real-time applications that require very low latency and jitter. TT traffic is transmitted based on schedule tables called Gate-Control Lists (GCLs) that rely on a global synchronized clock (802.1ASrev).
ATS, standardized as IEEE P802.1Qcr [3], was initially named Urgency-Based Scheduler (UBS) and, in the paper [4], it was defined as an asynchronous traffic scheduling algorithm, which gives low delay guarantees while maintaining a low implementation complexity. It also provides a temporally-composable timing analysis, see [4] for more details. Compared to the TT traffic type, ATS does not require schedule tables, which can be difficult to create, and compared to AVB, ATS guarantees lower latencies and has a simpler and faster timing analysis.
The purpose of this project is to compare the timing characteristics and flexibility of a system using either TT or ATS traffic type. In terms of timing properties we would like to study the jitter and WCD of critical traffic. In terms of flexibility we are interested to compare the deployment costs when (1) more traffic is added to the system and/or (2) the network is extended. Practically, the project is about doing a simulator for UBS and comparing the results with the scheduling tools that already exist for TT.
[1]: TSN Task Group. Time-Sensitive Networking. 2017 www.ieee802.org/1/pages/tsn.html
[2]: TSN Task Group. IEEE 802.1Qbv/D3.1 : Enhancements for Scheduled Traffic. 2015 www.ieee802.org/1/pages/802.1bv.html
[3]: TSN Task Group. IEEE P802.1Qcr/D0.2 : Bridges and Bridged Networks Amendment: Asynchronous Traffic Shaping. 2017
www.ieee802.org/1/pages/802.1cr.html
[4]: J. Specht and S. Samii. Urgency-Based Scheduler for Time-Sensitive Switched Ethernet Networks. Euromicro Conference on Real-time Systems. 75-85. 2016
Supervisor(s) Paul Pop
| Sidst opdateret: Nov 27, 2017 af Hans Henrik Løvengreen |