Hi,
I am hoping that someone may have experienced some of the following errors we are experiencing between a pair of 3750 Stacks via an EthoMPLS link. Recently we enabled spannning tree logging on both switches. The reason for this was that we were experiencing some topology changes and we wanted to try and trace where these were being generated from. since then we saw numerous topology changes between the primary 800M link and the secondary 100M link. Ok so to mitigate this we then shut the port down on the 100M eliminating the loop and expected to erradicate the changes imediately. However what we are now seeing is the same number of changes but now fliping between the 800M pfysical port and Stackport 2? Extract as follows;
Apr 24 22:08:47.427 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 785: New Root Port is GigabitEthernet1/0/36. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:08:47.440 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 785: New Root Port is StackPort2. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:13:55.035 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 684: New Root Port is GigabitEthernet1/0/36. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:13:55.045 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 684: New Root Port is StackPort2. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:20:15.258 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 649: New Root Port is GigabitEthernet1/0/36. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:20:15.270 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 649: New Root Port is StackPort2. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:20:47.636 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 760: New Root Port is GigabitEthernet1/0/36. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:20:47.675 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 760: New Root Port is StackPort2. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:24:44.785 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 413: New Root Port is GigabitEthernet1/0/36. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:24:44.790 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 413: New Root Port is StackPort2. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:46:53.752 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 501: New Root Port is GigabitEthernet1/0/36. New Root Mac Address is 68bc.0cea.df00
Apr 24 22:46:53.766 GMT: %SPANTREE-5-ROOTCHANGE: Root Changed for vlan 501: New Root Port is StackPort2. New Root Mac Address is 68bc.0cea.df00
So to summarise we had this continually when we had a redundant link and was flipping between the primary and secondary ports, then when we diabled the redundant link we have the same but now via the Stackport. the question is is this normal or anything to worry about. Our main concern obviously that mac tables are being flushed continually due to the topology changes as a switch should.
Any help advice in this matter would be greatly appreciated.
Regards
Darren
