Network Outage – Unexpected High CPU on Cisco Catalyst Switch

[MD Irshad Ansari]

Hi Cisco Community,

Last week we faced an unexpected issue in our network. Users were complaining about slow responses and intermittent outages. On checking one of the Catalyst switches, CPU utilization was spiking around 95-99%.

Steps we tried:

• Checked for spanning-tree loops but found none.
• Looked at processes with "show processes cpu sorted".
• Cleared ARP cache which reduced load temporarily.

My questions:

1. What are the common causes of sudden high CPU on Catalyst switches?
2. Do you recommend using control-plane policing (CoPP) or storm-control as prevention?
3. Any tips for identifying if the issue comes from client misconfigurations or external broadcast storms?

Thanks,
Irshad