Using Infineon's 88Q5152 automotive Ethernet SWITCHES device, IEEE802.1CB (FRER) is achieved without a microcontroller | NEXTY Electronics, an electronic components and semiconductor trading company

In-vehicle ECUs are connected via Ethernet. If communication is interrupted due to a broken CABLES or a faulty CONNECTORS, the driver assistance system (brake/steering control, etc.) will safely connect directly. To protect against this risk, redundancy with multiple paths between ECUs is required. A typical example is IEEE 802.1CB, which duplicates FRAMES and sends them down a different path, eliminating duplication on the receiving side.
The 88Q5152 automotive Ethernet SWITCHES device can achieve IEEE 802.1CB even in a configuration without an external microcontroller. This paper uses an 88Q5152 evaluation board to demonstrate the behavior of the device in the event of transmission duplication, reception duplication elimination, and one-side system disconnection, without using an external microcontroller or the 88Q5152's built-in CPU.

What are the features of the 88Q5152 device?

The 88Q5152 is a 9-port automotive Ethernet SWITCHES with built-in 1000BASE-T1 PHY and MACsec. Its unique feature is its ability to handle secure communications (MACsec) and AVB/TSN functions in inter-ECU networks on the same device. It also features a dual-core ARM R52 CPU and high-speed SerDes. It supports multiple TSN-related standards, including IEEE 802.1CB. This article focuses on 802.1CB, which enables redundancy.

What is IEEE802.1CB?

The currently published article, "What is IEEE802.1CB?" (https://www.nexty-ele.com/technical-column/ethernet_seamless/) provides an overview of IEEE802.1CB. This standard is a technology that improves communication redundancy and reliability by duplicating and transmitting the same FRAMES over multiple routes and identifying and discarding duplicate FRAMES on the receiving side.

IEEE802.1CB functionality realized with the 88Q5152 evaluation board

This time, we used the 88Q5152 evaluation board to achieve IEEE802.1CB without a microcontroller. The evaluation board does not have an external microcontroller connected to it. In addition, to clarify the microcontroller-less conditions, we disabled the built-in CPU of the 88Q5152 during testing.

FRAMES duplication on the sender side

We configured 88Q5152 for FRAMES duplication and output port specification, and confirmed that identical FRAMES with R-Tag were output from two ports (observation point: sending output port).
The verification contents and results are as follows:

Receiver FRAMES deduplication

For 88Q5152, we configured duplication removal and output port specification, and confirmed that the R-Tag was removed on the receiving side and only a single FRAMES with duplicates suppressed was output from the specified port (observation point: receiving side output port).
The verification contents and results are as follows:

Even when CABLES was unplugged and one of the paths was blocked, we confirmed that a single FRAMES was output on the receiving side after the R-Tag was removed.
The verification contents and results are as follows:

Summary

We have confirmed that IEEE802.1CB can be implemented without a microcontroller by using Infineon's in-vehicle Ethernet SWITCHES device, the 88Q5152. If you are considering adopting this standard, we believe it is worth considering the 88Q5152. We recommend that you first use an evaluation board to reproduce a configuration close to your company's, based on the verification conditions described in this article.