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Cisco Bug: CSCun86405 - Orphan Ports on FEX have the MAC learnt on ES ID instead of local SWID

Last Modified

Aug 07, 2019

Products (7)

  • Cisco Nexus 7000 Series Switches
  • Cisco Nexus 7000 10-Slot Switch
  • Cisco Nexus 7000 4-Slot Switch
  • Cisco Nexus 7700 18-Slot Switch
  • Cisco Nexus 7000 18-Slot Switch
  • Cisco Nexus 7700 10-Slot Switch
  • Cisco Nexus 7000 9-Slot Switch

Known Affected Releases

6.2(2)

Description (partial)

Symptom:
Orphan ports connected over FEX HIF may observe traffic getting black holed due to incorrect learning of MAC address in a VPC+ domain.
The MAC is learned from Emulated SWID (ESID) instead of Local SWID as observed on other switches in FabricPath Domain.

On the problem switch:
Software MAC learning would pick on the right physical port, though hardware MAC tables would shows MAC learned from ESID instead of Local SWID.

Conditions:
Problem may trigger if ports which were part of VPC+ complex (VPC port-channel) and were then moved to FEX-Fabric mode using channel-group force option. 
This does not clear the register setting properly and MAC learning still picks on ESID as is treated to be coming across a VPC+ Port-channel.

This is the only known and analyzed trigger though may not be the only one.
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Bug Details Include

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