Cisco Nexus vpc card type mismatch

ciscocisco-nexus-5kcisco-nx-osfexvpc

I have a pair of Nexus switches configured for vPCs. In several cases, it is working correctly: 

core01# sh vpc consistency-parameters int po40

    Legend:
        Type 1 : vPC will be suspended in case of mismatch

Name                        Type  Local Value            Peer Value
-------------               ----  ---------------------- -----------------------
mode                        1     active                 active
Speed                       1     1000 Mb/s              1000 Mb/s
Duplex                      1     full                   full
Port Mode                   1     access                 access
MTU                         1     1500                   1500
Admin port mode             1
Shut Lan                    1     No                     No
vPC card type               1     FEX                    FEX
Allowed VLANs               -     1052                   1052
Local suspended VLANs       -     -                      -

However, in several cases, it is not: 

core01# sh vpc consistency-parameters int po60

    Legend:
        Type 1 : vPC will be suspended in case of mismatch

Name                        Type  Local Value            Peer Value
-------------               ----  ---------------------- -----------------------
vPC card type               1     Empty                  FEX
Allowed VLANs               -     1-4094                 1-4094
Local suspended VLANs       -     -                      -

On the partner switch, the local and peer values match what core01 reports: 

core02# sh vpc consistency-parameters int po60

    Legend:
        Type 1 : vPC will be suspended in case of mismatch

Name                        Type  Local Value            Peer Value
-------------               ----  ---------------------- -----------------------
vPC card type               1     FEX                    Empty
Allowed VLANs               -     1-4094                 1-4094
Local suspended VLANs       -     -                      -

I haven't been able to figure out why the vPC card type is reporting as Empty.

Any ideas or troubleshooting steps I could try?

Best Answer

The problem is due to a Cisco bug CSCuq60111. Since the bug tool is not for everyone i will post the solution from Cisco here:

Incorrect Type 1 vPC consistency for "vPC card type" in Enhanced vPC CSCuq60111

Description

Symptom:

show vpc consistency-parameters interface port-channel 

Name                        Type  Local Value            Peer Value             
-------------               ----  ---------------------- -----------------------
vPC card type               1     FEX                    Empty                       -> Peer1 output
vPC card type               1     Empty                  FEX                         -> Peer2 output
OR
vPC card type               1     Empty                   Empty                      -> Peer1 output
vPC card type               1     Empty                   Empty                      -> Peer2 output

Conditions:

While configuring enhanced vPC on Nexus 6000 for first time or when recent reload has performed on both peers. We may see "vPC card type" Value mismatch on vpc peers. - Expected output is 

Name                        Type  Local Value            Peer Value             
-------------               ----  ---------------------- -----------------------
vPC card type               1     FEX                    FEX                        -> Peer1 output
vPC card type               1     FEX                    FEX                        -> Peer2 output

Workaround:

  • Shut on FEX up-link port-channels on both vPC peers FIRST and then no-shut on both sides.

Note:- Fex interfaces will go offline when uplinks are disabled on both vpc peers

Further Problem Description:

This behavior does not affect functionality of FEX or Host connected to HIF interfaces.

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