What Are the Common Causes for STP Flapping?

Created Mar 07, 2016 10:55:40Latest reply Nov 09, 2016 23:49:59 2289 5 0 0

The packet change and timer timeout repeatedly triggers recalculation and makes network switches constantly repeat the following process: 1. Root bridge selection; 2. Port role switch; 3. Port status migration. Repetition of this process for many times is called STB flapping, which cannot be converged.

The common causes are as follows:
  • Link fault: The link attributes such as the port status, rate, and duplex mode of a port on the network constantly change.
  • Node fault: A switch has high CPU usage and cannot send or process STP packets at specified intervals.
  • Network fault: The network is congested, making the STP packets in the direction of root port be discarded in the process of forwarding. L2PT transparently transmits STP packets of other networks, making the STP of the port converge mistakenly. The multicast suppression function is incorrectly configured on the network, making STP packets be discarded occasionally.
Modify configuration or optimize the network design based on different causes to rectify the STP flapping.

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Nana00  Novice   Created Mar 09, 2016 09:30:02 Helpful(0) Helpful(0)

Thank you for sharing.
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SherryL  Adept   Created Mar 07, 2016 13:41:18 Helpful(0) Helpful(0)

Thank you.
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ictofsajjad     Created Oct 01, 2016 20:20:59 Helpful(0) Helpful(0)

if ONE-WAY link fault occurs & LOOP PROTECTION feature is not configured... ""ictofsajjad""
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Entrepreneur     Created Oct 25, 2016 15:50:03 Helpful(0) Helpful(0)

Thanks for sharing!
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CippaLippa     Created Nov 09, 2016 23:49:59 Helpful(0) Helpful(0)

Thank you for sharing.
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