Had a spanning tree loop yesterday and had an awful time tracking it down. I have read all of the doco on how to detect but saw very few symptoms. Does anyone have any good info or insight on how to quickly diagnose and identify a Span tree loop? We are running 6509s with 12.2 (18) code sup 720s. When we had SUP2s it was easy because the cpu would spike to 90%. The 720s barely notice. They never went over 25%.