The VPC uplink on Nexus 5672UP Chassis faced the *PVID_Inc issue.

Hardware & Software details:

Nexus 5672UP Chassis :   kickstart version 7.1(0)N1(1b) & system version 7.1(0)N1(1b)
Nexus 7010 Chassis :  kickstart version 5.2(4) & system version 5.2(4)

Observation on Nexus 5K:  STP root for VLAN 1 become one of the N5K and the uplink ports become blocked with error "*PVID_Inc". This message usually comes when the Native VLAN configuration miss-match in configuration on interface level. However in this case, the configuration was very straight forward with default Native VLAN 1. But the error appeared in both N5K and we were not able to access the management IP on Nexus 5K itself.

This TechNotes explains about the possible reason for *PVID_Inc - http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24063-pvid-inconsistency-24063.html#topic2

N5K-1# show spanning-tree

VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    32769
             Address     00de.fb07.517c
             This bridge is the root
             Hello Time  2  sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     00de.fb07.517c
             Hello Time  2  sec  Max Age 20 sec  Forward Delay 15 sec

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po11             Desg BKN*1         128.4106 (vPC) P2p *PVID_Inc
Po100            Desg FWD 1         128.4195 (vPC peer-link) Network P2p

N7K-1# show spanning-tree vlan 1

VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    4097
             Address     0023.04ee.be01
             Cost        1
             Port        4195 (port-channel100)
             Hello Time  2  sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    8193   (priority 8192 sys-id-ext 1)
             Address     0023.04ee.be01
             Hello Time  2  sec  Max Age 20 sec  Forward Delay 15 sec

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po1              Desg FWD 1         128.4096 (vPC) P2p
Po2              Desg FWD 1         128.4097 (vPC) P2p
Po3              Desg FWD 1         128.4098 (vPC) P2p
Po4              Desg FWD 1         128.4099 (vPC) P2p
Po5              Desg FWD 1         128.4100 (vPC) P2p
Po6              Desg FWD 1         128.4101 (vPC) P2p
Po7              Desg FWD 1         128.4102 (vPC) P2p
Po8              Desg FWD 1         128.4103 (vPC) P2p
Po10             Desg FWD 1         128.4105 (vPC) P2p
Po11             Desg FWD 1         128.4106 (vPC) P2p
Po100            Root FWD 1         128.4195 (vPC peer-link) Network P2p
Eth8/17          Desg FWD 2         128.1041 P2p Peer(STP)
Eth8/18          Desg FWD 2         128.1042 P2p Peer(STP)

N5K-1# show int po11 switchport
Name: port-channel11
  Switchport: Enabled
  Switchport Monitor: Not enabled
  Operational Mode: trunk
  Access Mode VLAN: 1 (default)
  Trunking Native Mode VLAN: 1 (default)
  Trunking VLANs Allowed: 1-4094
  Voice VLAN: none
  Extended Trust State : not trusted [COS = 0]
  Administrative private-vlan primary host-association: none
  Administrative private-vlan secondary host-association: none
  Administrative private-vlan primary mapping: none
  Administrative private-vlan secondary mapping: none
  Administrative private-vlan trunk native VLAN: none
  Administrative private-vlan trunk encapsulation: dot1q
  Administrative private-vlan trunk normal VLANs: none
  Administrative private-vlan trunk private VLANs: none
  Operational private-vlan: none
  Unknown unicast blocked: disabled
  Unknown multicast blocked: disabled

N7K-1# sh int port-channel 11 switchport
Name: port-channel11
  Switchport: Enabled
  Switchport Monitor: Not enabled
  Operational Mode: trunk
  Access Mode VLAN: 1 (default)
  Trunking Native Mode VLAN: 1 (default)
  Trunking VLANs Allowed: 1-4094
  FabricPath Topology List Allowed: 0
  Administrative private-vlan primary host-association: none
  Administrative private-vlan secondary host-association: none
  Administrative private-vlan primary mapping: none
  Administrative private-vlan secondary mapping: none
  Administrative private-vlan trunk native VLAN: none
  Administrative private-vlan trunk encapsulation: dot1q
  Administrative private-vlan trunk normal VLANs: none
  Administrative private-vlan trunk private VLANs: none
  Operational private-vlan: none

Finally, we have upgraded the code on N5K to latest recommended code and without even doing any further configuration changes, the *PVID_Inc issue for resolved.

  kickstart: version 7.1(4)N1(1)
  system:    version 7.1(4)N1(1)

Any of you have faced very similar issues? Does this issue resolved in any other way. Appreciate on your inputs.

Regards,

Balaji Rajan