have some questions about a recent STP issue in our network. After reviewing several Cisco STP design & troubleshooting guides, the documents repeatedly indicate that a STP failure is usually the result of a blocked port transitioning to forwarding mode, thereby causing a loop.
- is this truly the cause of most STP failure issues?
- if so, would it make sense to determine where the blocked ports are in the network and focus our attention on those ports for:
portfast config errors,
stp parameter tuning, as per the design guides ??
- or, is there another major cause of STP failure we should be looking at?