The common cause for link flapping is usually related to bad, unsupported, or non-standard cable or Small Form-Factor Pluggable (SFP) or related to other link synchronization issues. If you have physical access to the switch, it can save time to look at the port LEDs which give you the link status or can indicate an error condition (if red or orange). By understanding and resolving these issues, you can maintain a resilient network infrastructure. If the entire switch is unresponsive, or. A port flap, also referred to as a link flap, is a situation in which a physical interface on the switch continually goes up and down, three or more times a second for duration of at least ten seconds. The root cause of these issues tend to be simple in nature, such as a failing optic/transceiver or bad medium (like a damaged fiber or copper cable). I'm sure I removed the correct VLANs. When I saved the configuration, everything stopped working and now we don't know what to do.
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