Modeling and Analysis of 10Base-T1S Network with IEEE 802.1Qav Traffic Shaping

Abstract

Base-T1S Ethernet is a promising technology for integrating low-rate electronic control units (ECUs) in invehicle and industrial networks, because it supports multidrop communication over a single-pair physical layer while preserving an Ethernet-based architecture. Its Physical Layer Collision Avoidance (PLCA) mechanism assigns deterministic transmission opportunities to nodes in a round-robin manner. IEEE 802.1Qav Credit-Based Shaper (CBS) is widely adopted in TSN/AVB networks to regulate class-based bandwidth and suppress traffic burstiness, and can be deployed locally within each ECU before frames are forwarded to the PLCA MAC-PHY. Existing CBS analyses typically assume full-duplex point-to-point Ethernet links, where an eligible queue, once selected by the local scheduler, can receive continuous transmission service at the link rate. This assumption does not directly hold in PLCA-based multidrop networks, where an ECU can transmit only during its assigned transmission opportunities. For control, diagnostic, and safety-related traffic, average delay or finite simulation traces are insufficient to certify whether timing requirements are always met; designers instead need deterministic upper bounds on the worst-case delay. However, in PLCA-based 10Base-T1S networks, the service available to CBS-shaped traffic is determined by the interaction among CBS credit evolution, PLCA access timing, and local non-preemptive priority scheduling. Therefore, these mechanisms must be modeled jointly to derive such bounds. This paper develops a network-calculus model for CBS-shaped traffic over PLCA-based 10Base-T1S networks. Numerical examples and simulation results demonstrate how CBS parameters and PLCA configurations influence the resulting delay bounds.