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Cisco Bug: CSCvh77023 - Veth number is conflicting on secondary switch after UCS reload

Last Modified

Aug 13, 2019

Products (1)

  • Cisco Nexus 5000 Series Switches

Known Affected Releases

7.1(4)N1(1)

Description (partial)

Symptom:
[+] (x2) Nexus 5500 in VPC with two single homed FEX 2232 using adapter-fex allows configuration of the same Veth (Veth32829) on both the VPC primary and secondary mapping to two different VIF indexs:

JKT-MB-011DC-NX005-SS001# show interface virtual status
Interface VIF-index   Bound If      Chan  Vlan  Status     Mode     Vntag
-------------------------------------------------------------------------
Veth32829 VIF-542     Eth105/1/14      7   110  Up         Active   8    


JKT-MB-011DC-NX006-SS002# show interface virtual status
Interface VIF-index   Bound If      Chan  Vlan  Status     Mode     Vntag
-------------------------------------------------------------------------
Veth32829 VIF-76      Eth106/1/2       2   120  Up         Active   3

[+] Above having the same Veth for a different VIF is not expected in the topology explained above and after a reload the VPC secondary notices this difference and error-disables some ports:

KT-MB-011DC-NX006-SS002# show logging logfile
2017 Oct 30 03:52:05 JKT-MB-011DC-NX006-SS002 %VIM-5-VETH_NUMBER_CONFILCT: Interface Vethernet32829 is down because the veth number is different from the veth on primary switch

Conditions:
[+] Same Veth is configured for a different VIF index:

JKT-MB-011DC-NX005-SS001# show interface virtual status
Interface VIF-index   Bound If      Chan  Vlan  Status     Mode     Vntag
-------------------------------------------------------------------------
Veth32829 VIF-542     Eth105/1/14      7   110  Up         Active   8    


JKT-MB-011DC-NX006-SS002# show interface virtual status
Interface VIF-index   Bound If      Chan  Vlan  Status     Mode     Vntag
-------------------------------------------------------------------------
Veth32829 VIF-76      Eth106/1/2       2   120  Up         Active   3

[+] UCS that uses these Veths is reloaded and the VPC secondary sees the conflict Veths and error disabled the Veth on the VPC secondary.
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