Disable the MSTP when switches are in loop

[satyanarayana]

Hello Vitalii,

Kindly let us know the validation of the following scenario.

Steps are as follows,
1. Enable the MSTP on all 4 switches.
2. Create the topology as below,

a. Switch 1 and switch 4 are connected in loop and are in same region REG1
b. Switch 2 and switch 3 are connected in loop and are in same region REG2
c. Switch 1 have one link connected to Switch 2

Loops are prevented by MSTP and working as expected.

1. Now disable the MSTP on all switches.
2. Enable the MSTP after some time on all 4 switches (Failed to avoid the loop)

Kindly let us know wheteher the above mentioned scenario is valid (Can we enable the MSTP when switches are already in loop?).

Regards,
Satyanarayana

[Vitalii Demianets]

Hello Satyanarayana!
Of course the scenario is valid, you can do whatever you want but at the end of the day MSTP should break all the loops.
Can you please give me more thorough description of your topology (which ports are connected) and which exactly commands do you issue, so that I can reproduce the issue here.

PS. Please also specify which revision of mstpd you are using. There was a couple of fixes recently, although I believe they are not relevant to your issue.

Best regards,
Vitalii