AM4376: State changing Issues While working with RSTP.

Hi Prajwal Khatavkar,

Thanks for your query.

Which SDK are you working on ?

Regards

Ashwani

Hi Ashwani,

I am using  ti-processor-sdk-linux-am437x-hs-evm-06-03-00-106.

Thank you for your response. Eagerly waiting for Solutions.

Regards,

Prajwal.

"eth0 operates correctly in RSTP mode when added to the bridge using 'brctl addif br0 eth0'. However, executing 'brctl addif br0 eth1' to include eth1 unexpectedly disables both eth0 and eth1. We require both eth0 and eth1 for redundancy."

Hi Ashwani,

I am attaching some screenshots for your reference I hope this helps.

Hi Prajwal Khatavkar,

Thanks for logs.

I am forwarding your query to Linux Ethernet expert.

Regards

Ashwani

Hi,

Are the CPSW interfaces being used for this application?

Has RSTP been enabled in the kernel configuration?

Can you provide the steps you used to setup the bridge?

Could you please describe the redundancy that is needed? Could attach a block diagram of the network topology? 

Best Regards,

Schuyler

Hi Schuyler,

Thank you for your valuable input.

1. CPSW Interfaces:

Based on the absence of CPSW-related output from dmesg | grep cpsw and lsmod | grep cpsw, it can be concluded that CPSW interfaces are not being used in this application. The system likely utilizes general-purpose Ethernet interfaces (e.g., eth0, eth1) provided by the AM4376.

2. RSTP in Kernel Configuration:

The CONFIG_BRIDGE=m and CONFIG_BRIDGE_NETFILTER=m kernel configuration options indicate that the bridge and Netfilter bridge modules are compiled as loadable.

3. Bridge Setup Steps:

brctl addbr br0
ip link set dev br0 up
brctl stp br0 on
brctl addif br0 eth0
brctl addif br0 eth1
sudo systemctl start mstpd
sudo systemctl enable mstpd
sudo mstpctl setforcevers br0 rstp
sudo mstpctl showbridge br0
sudo mstpctl showport br0

4. Redundancy Requirement:

The primary redundancy requirement is to ensure network connectivity even if one of the Ethernet interfaces (eth0 or eth1) fails.
This is crucial for maintaining system stability and preventing service interruptions.
Current Observations:

The brctl showstp br0 output shows that both eth0 and eth1 are "disabled". This is unexpected as at least one port should be in the "forwarding" state for proper operation.

I am attaching the block diagram you asked for.

The primary redundancy requirement is to ensure network connectivity even if one of the Ethernet interfaces (eth0 or eth1) fails in this ring topology.

Please let me know if you need anything further.

regards,

Prajwal.

Hi Schuyler,

I hope you are doing well. I have an observation that may help you debug the issue As I mentioned earlier. Only one Ethernet interface works correctly, and it does not depend on whether eth0 or eth1.

Whichever you configure first will work fine. However, if you add another interface, both interfaces become stuck in a disabled state.

I am eagerly awaiting your valuable input. Please get back to me as soon as possible.

Best Regards,

Prajwal

Hi Schuyler,

For your reference, the relevant software versions are:

• SDK:  06.03.00.106
• U-Boot:  2023.04
• Kernel:  Linux-rt-5.10
• Firmware: /resized-image/__size/320x240/__key/communityserver-discussions-components-files/791/Screenshot-from-2025_2D00_01_2D00_21-14_2D00_52_2D00_29.png

This information might be helpful in your investigation of the issue with multiple Ethernet interfaces.

Best Regards,

Prajwal

Hi Schuyler ,

I Am eagerly awaiting your inputs please get back to me as soon as possible.

Regards,

Prajwal.