What is Device Flapping?

Network device flapping occurs when a network device repeatedly connects and disconnects in short intervals. This issue affects stability and can cause network disruptions. Flapping is commonly seen in links between switches, routers, or access points due to faulty cables, hardware failures, or configuration errors. It can also result from spanning tree recalculations, interface errors, or unstable power sources. Network administrators use logs, SNMP traps, and monitoring tools to detect and troubleshoot flapping devices.

Storm Control, Flow Control, and LLDP Filter do not directly prevent device flapping, but they can help reduce the impact of certain causes of flapping. Here’s how:

1. Storm Control – Limits broadcast, multicast, and unknown unicast traffic. If flapping is caused by excessive broadcasts (e.g., from a switching loop), Storm Control can mitigate network congestion but will not stop the root cause of flapping.
2. Flow Control – Manages data transmission rates between devices to prevent congestion. If flapping is caused by buffer overflows or packet loss due to congestion, Flow Control may help stabilize the connection. However, it does not fix unstable physical links or redundant path switching issues.
3. LLDP Filter – Prevents unnecessary LLDP packets, and prevents false alerts in the presence of unmanaged switches.

Content created by Mike Day