Presentation Information
[B-16-03]A Study on Delay Analysis of a Credit-Freeze CBS Policy over 10Base-T1S PLCA Networks
◎Taiki Nonaka1, Han Nay Aung1, Yasuhiro Yamasaki2, Hiroyuki Ohsaki1 (1. Kwansei Gakuin Univ., 2. Chukyo Univ.)
Keywords:
10Base-T1S,PLCA,automotive network,network calculus
With the proliferation of automated driving, the adoption of the automotive Ethernet standard 10Base-T1S is steadily increasing. While this standard avoids physical-layer collisions using the PLCA (Physical Layer Collision Avoidance) mechanism, the coexistence of multiple traffic classes with differing delay requirements necessitates bandwidth guarantees and burst smoothing via the IEEE 802.1Qav Credit-Based Shaper (CBS). However, conventional CBS analyses assume full-duplex links, leaving the behavior and delay characteristics in PLCA networks—where transmission opportunities rotate among nodes—largely unclarified. This paper focuses on a "Credit-Frozen CBS Policy," which freezes AVB (Audio Video Bridging) class credits outside of a node's own transmission opportunity or during the transmission of higher-priority traffic, and proposes a method for deriving the worst-case upper bound delay using network calculus. Furthermore, comparative evaluations with discrete-event simulations demonstrate that the derived delay upper bound safely exceeds the simulation values, proving its utility for conservative evaluation during the initial stages of design.