Hi,

I try to setup a simple MSTP and it works not as expected.
I have set-up two router with the same VLANs (11 and 21) and created a MSTP instance.

Root:
The salve bridge behaves as expected:

So far everything works as expected, VLAN 11 and 21 go through ether4.

Now I want VLAN11 to go through ether4 and VLAN21 through ether5.
I edit the port priority of the root bridge as follwing: ether4 = ID11 = VLAN11 = 70
ether4 = ID21 = VLAN21 = 80
ether5 = ID11 = VLAN11 = 80
ether5 = ID21 = VLAN21 = 70


THE RPOBLEM: The slave bridge ignores the priority setting of the root-bridge: Everything still goes through ether4.

What do I wrong??

Is this a bug in ROS or in my head??

The Wirshark-Output is from the salve-bridge (NOT the root-bridge), the received frames are FROM the root-bridge.

ROS transmitts always the sequence: 0b0100.0000
0b0100 = 0x4 = 0b0100.0000 = 0x40

Reagrdless of what is configured 0x80 (0b1000.0000):


OK, now we change the Port-Priority to 0x10 (0b01000.0000):
Now, ROS transmitts 0b0000.0000 insted of 0b0001.0000 (0x10):

I am totaly wrong (or crazy - doing this stuff for hours), or is this a bug???

And its getting better, the behaviour is other after a reboot:

PRIOR the reboot: 0x80 is configured:
Transmitts 0x0 instead of 0x1000.0000:
NOW we reboot the device...

Same config:
But now 0x40 (0b0100.0000) is transmitted insted of 0x80 (0b1000.0000):


Now with 0xf0 (0b1111.0000):
PRIOR reboot 0x0:
AFTER reboot again 0x4 instead of 0xfb:
This erratic behaviour would correlate to my finding from the original post.
I seems something is wrong with ROS....??