Hi,
Yes you are correct in that I have enabled Loopback Detection globally (but on EVERY switch).
I have "loopback-detection enable" on all interfaces.
In addtion, on the trunk ports, I have "loopback-detection control enable" and "loopback-detection per-vlan enable".
The LAN is in and working fine apart from these LPDETECT_BLOCK & LPDETECT_RECOVER errors which have an impact. I have VLAN's split across the fibre uplinks with failiver and its working a treat :)
In fact I have just discovered that I have "stp loop-protection" on g1/0/26 on both SWITCH-05 & -06. Have just removed that as they were the only two with it and the only two that exhibit the problem (so far as I can tell by looking at logs which only go back a week or so). Will see if that makes any difference although I am not too hopeful.
Looking at the logs I have come up with the following sequence of events:
09.59.38 SWITCH-03 BAGG2 Instance 0,1,2 No BDPU received
10.00.09 SWITCH-02 BAGG2 Inst 0,1,2 detected topology change
BAGG2 is set to FORWARDING Inst 0,1,2
10.00.10 SWITCH-01 BAGG2 Inst 0 detected toopolgy change
10.00.12 SWITCH-04 Int g1/025 Inst 0 detected topology change
10.00.14 SWITCH-00 BAGG1 Inst 0 detected topology change
10.00.12 SWITCH-05 Int g1/0/25 Inst 0 Topology Change
LPDETECT_BLOCK on g1/0/25 and g1/0/26 (fibres)
10.00.27 SWITCH-02 Inst 0,1,2 BAGG2 set to discard
10.01.52 SWITCH-05 LPDETECT_RECOVERED on g1/0/25 and g1/0/26