Questions: Network Experiencing Broadcast Storm and High CPU on Switches

• What is the current CPU utilization on the affected switches?
• Are there MAC address flapping messages in the switch logs, and on which ports?
• Is Spanning Tree Protocol (STP) enabled on all switches and VLANs?
• What STP state are the ports in -- are any ports that should be blocking in forwarding?
• Was any new equipment (switch, AP, cable) added to the network recently?
• Could a physical loop have been created (e.g., patch cable connecting two ports on the same switch)?
• Are storm control or BPDU guard features configured on access ports?
• What does the MAC address table show -- is it full or thrashing?
• Are trunk ports showing abnormally high utilization?
• Which specific ports or links are involved in the loop?