Software-Based Time-Aware Shaper for Time-Sensitive Networks

Yasin OGE  Yuta KOBAYASHI  Takahiro YAMAURA  Tomonori MAEGAWA  

IEICE TRANSACTIONS on Communications   Vol.E103-B   No.3   pp.167-180
Publication Date: 2020/03/01
Publicized: 2019/09/09
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2019EBT0001
Type of Manuscript: PAPER
Category: Network
time-sensitive networking,  TSN,  IEEE 802.1Qbv,  time-aware shaper,  

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This paper presents the design, implementation, and evaluation of a time-aware shaper, which is a traffic shaper specifically designed for IEEE 802.1Qbv-compliant time-sensitive networks. The proposed design adopts a software-based approach rather than using a dedicated custom logic chip such as an ASIC or FPGA. In particular, the proposed approach includes a run-time scheduler and a network interface card (NIC) that supports a time-based transmission scheme (i.e., launch-time feature). The run-time scheduler prefetches information (i.e., gate control entry) ahead of time from a given gate control list. With the prefetched information, the scheduler determines a launch time for each frame, and the NIC controls the time at which the transmission of each frame is started in a highly punctual manner. Evaluation results show that the proposed shaper triggers transmission of multiple time-sensitive streams at their intended timings in accordance with a given gate control list, even in the presence of high-bandwidth background traffic. Furthermore, we compare the timing accuracy of frame transmission with and without use of the launch-time feature of the NIC. Results indicate that the proposed shaper significantly reduces jitter of time-sensitive streams (to less than 0.1 µs) unlike a baseline implementation that does not use the launch-time feature.