clean up VPC on Nexus 5000 K switches

[thiyagarajankalaiselvan]

Hi Team,

I'm seeing the below error in Nexus 5K environment. We do not have VPC configured for that interface and when I check the VPC status and I'm seeing "consistency check not performed" message.

I have tried shutting down and unshut the interface and I'm still seeing the interface in the VPC brief output with the same error message.

# sh vpc brief

102423 Eth101/1/24 down*  Not         Consistency Check Not      -
                                         Applicable   Performed
 

sh run int Ethernet101/1/24

interface Ethernet101/1/24
  switchport access vlan 9
  spanning-tree port type edge
  no snmp trap link-status

Can you please help me to get away from the status message "Consistency check not formed" or interface status is down?

Do I need to reset the interface to fix this issue?

Regards,

Thiyagu

[Mark Malone]

what does show vpc consistency-parameters Ethernet101/1/24 ----output show

Is the port operational and up will show this by default if not

[thiyagarajankalaiselvan]

Please find below the requested output.

#sh vpc consistency-parameters interface Ethernet101/1/24

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

Name                        Type  Local Value            Peer Value
-------------               ----  ---------------------- -----------------------
Allowed VLANs               -     9                      9
Local suspended VLANs       -     -                      -

Interface configuration:

VPC brief output for an interface  Eth101/1/24:

#102423 Eth101/1/24 down*  Not         Consistency Check Not      -
                                            Applicable  Performed
 

Running configuration of an interface:

#interface Ethernet101/1/24
  switchport access vlan 9
  spanning-tree port type edge
  no snmp trap link-status
 

I would like to know though the interface is not configured any VPC, why the VPC brief output show the status down?

Regards,

Thiyagu

[Steve Fuller]

Hi Thiyagu,

Is the FEX dual homed to two upstream Nexus switches? If so, do you have the same configuration applied for the interface on both of those switches?

Regards

[thiyagarajankalaiselvan]

Hi Steve,

Fex is not dual homed. Fex ports were connected to the servers.

Is this the behavior of Nexus 5 as I'm finding the same status for all the local interface which are down and are not part of any VPC?

Any of your help to drill down to find the reason is appreciable.

# sh vpc brief | i down

102433 Eth101/1/34 down*  Not         Consistency Check Not      -
102434 Eth101/1/35 down*  Not         Consistency Check Not      -
102435 Eth101/1/36 down*  Not         Consistency Check Not      -
102436 Eth101/1/37 down*  Not         Consistency Check Not      -
102437 Eth101/1/38 down*  Not         Consistency Check Not      -
102438 Eth101/1/39 down*  Not         Consistency Check Not      -
102439 Eth101/1/40 down*  Not         Consistency Check Not      -
102440 Eth101/1/41 down*  Not         Consistency Check Not      -
102441 Eth101/1/42 down*  Not         Consistency Check Not      -
102442 Eth101/1/43 down*  Not         Consistency Check Not      -
102443 Eth101/1/44 down*  Not         Consistency Check Not      -
102444 Eth101/1/45 down*  Not         Consistency Check Not      -

Regards,

Thiyagu
 

[Steve Fuller]

How is the connectivity between the FEX and the upstream Nexus switch configured? Do you use static pinning or created a port-channel with the physical ports to the FEX configured as members of that port-channel?

If you use a port-channel, can you attach or paste the output of a sh run int port-ch <port_channel_number> to the post?

Regards

[thiyagarajankalaiselvan]

Hi Steve,

Here is the FEX configuration and the FEX is connected to two upstream 5K switches. 

fex 101
  pinning max-links 1
  description "FEX0101"
  type N2248T

interface port-channel1501
  description FEX_vpc
  switchport mode fex-fabric
  fex associate 101
  vpc 1501

sh port-channel summary interface port-channel1501
Flags:  D - Down        P - Up in port-channel (members)
        I - Individual  H - Hot-standby (LACP only)
        s - Suspended   r - Module-removed
        S - Switched    R - Routed
        U - Up (port-channel)
        M - Not in use. Min-links not met
--------------------------------------------------------------------------------
Group Port-       Type     Protocol  Member Ports
      Channel
--------------------------------------------------------------------------------
1501  Po1501(SU)  Eth      NONE      Eth1/11(P)

interface Ethernet1/11
  description FEX101:2248T:Copper
  switchport mode fex-fabric
  fex associate 101
  channel-group 1501

Please let me know if you need any more information on this.

Regards,

Thiyagu

[Steve Fuller]

OK.... now I'm confused :-)

In an earlier response you'd state "Fex is not dual homed", but in this last response you state "the FEX is connected to two upstream 5K switches".

So if the FEX is dual homed i.e., some FEX network interface connect to N5K1 and some connect to N5K2, then this message is normal for any host interface that is operationally down.

If on the other hand, the FEX is single attached i.e., all FEX network interfaces connect to a single Nexus 5K, then you don't need the vpc 1501 command under interface port-channel 1501. I think that in this case the message would be appearing because of the vpc 1501 command.

Regards

[thiyagarajankalaiselvan]

Steve,

I'm sorry. Earlier I did not checked the configuration. FEX is dual homed.

Thanks for your reply. Does it mean if a FEX is connected to two upstream switches and uplink is bundled and configured in a VPC, Then we will see the VPC status of FEX switch ports down for the switch ports which are physically down.

Please correct me if I'm wrong.

Regards,

Thiyagu

[Steve Fuller]

Hi Thiyagu,

"Does it mean if a FEX is connected to two upstream switches and uplink is bundled and configured in a VPC, Then we will see the VPC status of FEX switch ports down for the switch ports which are physically down."

Yes. When you dual home a FEX it is essentially using Enhanced vPC (see Using Enhanced vPC) and the switches assign an internal vPC ID for each interface. This is the reason the interfaces are seen when you run the command show vpc brief. If you run the command show system internal vpcm info interface eth101/1/24 then it will show as "Interface configured as vPC".

This same behaviour has been seen by others (see show vpc output with EvPC  and Dual home FEX and VPC question) and it’s perfectly normal for these to show down when not operational.

Regards

[sbhadrav@cisco.com]

Possible Cause

vPC is not operational if type 1 consistency parameters do not match on both Nexus 5000 switches.

Solution

Ensure that type 1 consistency parameters match.

The possible values for type are 1, 2, or -. Items that are type 1 must match on both Nexus 5000 switches. If they do not match, then vPC is suspended. Starting with Release 5.0, a type 2 was introduced. Items that are type 2 do not have to match on both Nexus 5000 switches for the vPC to be operational.

The command in the following example displays local and peer values. Run the command on both switches to ensure that the type 1 items match.

Example:

To check for a mismatch, display the consistency parameters.

switch1# show vpc consistency-parameters global
 
Legend:
Type 1 : vPC will be suspended in case of mismatch
 
Name Type Local Value Peer Value
------------- ---- ---------------------- -----------------------
QoS 1 ([], [3], [], [], [], ([], [3], [], [], [],
[]) [])
Network QoS (MTU) 1 (1538, 2240, 0, 0, 0, (9216, 2240, 0, 0, 0,
0) 0)
Network Qos (Pause) 1 (F, T, F, F, F, F) (F, T, F, F, F, F)
Input Queuing (Bandwidth) 1 (50, 50, 0, 0, 0, 0) (50, 50, 0, 0, 0, 0)
Input Queuing (Absolute 1 (F, F, F, F, F, F) (F, F, F, F, F, F)
Priority)
Output Queuing (Bandwidth) 1 (50, 50, 0, 0, 0, 0) (50, 50, 0, 0, 0, 0)
Output Queuing (Absolute 1 (F, F, F, F, F, F) (F, F, F, F, F, F)
Priority)
STP Mode 1 Rapid-PVST Rapid-PVST
STP Disabled 1 None None
STP MST Region Name 1 "" ""
STP MST Region Revision 1 0 0
STP MST Region Instance to 1
VLAN Mapping
STP Loopguard 1 Disabled Disabled
STP Bridge Assurance 1 Enabled Enabled
STP Port Type, Edge 1 Normal, Disabled, Normal, Disabled,
BPDUFilter, Edge BPDUGuard Disabled Disabled
STP MST Simulate PVST 1 Enabled Enabled
Allowed VLANs - 1,19,91,99,120,757 1,10,19-20,91,99,400-4
01,403,420,440,442,444
-446,451-486,499,757,7
97
Local suspended VLANs - 120 -