network bridging

[Lxw2015]

Hi, I have RPi 4 connect to a RPi3 via usb C . so rpi3 usb0 network interface shows up. on RPi 3, I set a bridge
brctl addbr br0
brctl addif br0 eth0, usb0.

ping works between RPi3 and RPi4.

when RPi reset. I expect ping still work. but I was wrong.
then I show RPi3 bridge. brctl show br0
and discovered, usb0 is not in bridge br0 anymore. brctl addif br0 usb0. then ping worked again.

I wonder how to add the usb0 automatically into br0, when usb0 is available.

thanks
Lxw2015

[epoch1970]

You can use systemd-networkd, as in this example.
https://www.raspberrypi.org/documentati ... bridged.md

In your case you’d need an extra file “ br0-member-usb0.network”

Dhcdpc configures the bridge, on raspios.

[Lxw2015]

thank you so much. it worked.