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Cisco Bug: CSCuq89655 - N5k - VLAN may not be in forwarding STP state in FWM for a trunk port

Last Modified

Sep 09, 2019

Products (7)

  • Cisco Nexus 5000 Series Switches
  • Cisco Nexus 5548P Switch
  • Cisco Nexus 5596UP Switch
  • Cisco Nexus 5020 Switch
  • Cisco Nexus 5548UP Switch
  • Cisco Nexus 5010 Switch
  • Cisco Nexus 5596T Switch

Known Affected Releases


Description (partial)

N5k switch may not find one or more VLAN's in STP FWD state in respect to FWM, while other processes/features might not detect the same. This may lead to traffic getting blackholed and no MAC learning taking place.

Trigger is not known at this moment. When problem appears no MAC learning for a specific vlan or set of vlans would take place on particular trunk port. In case of vPC the affected switch may still learn MAC from peer switch for the VLAN which is not correctly programmed in hardware. Though no new learn takes place.
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Bug Details Include

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