Cisco 3650 log shows Line protocol bouncing on a port not connected to any device

[hemantpatel]

I have a  WS-C3650-48TS running on IOS ver 16.6.7.

I have seen log entries like following for the interfaces where no device is connected.

I have seen similar logs entries for interface Gi1/013 & Gi1/0/14.

There are no other log entries other than the line protocol up/down so nothing else is going on.

Log Entries:

*Dec 23 11:17:30: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/16, changed state to up
*Dec 23 11:17:32: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/16, changed state to down
*Dec 24 19:25:56: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/16, changed state to up
*Dec 24 19:25:59: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/16, changed state to down

Interface config:

interface GigabitEthernet1/0/13
switchport access vlan 30
end

interface GigabitEthernet1/0/14
switchport access vlan 2

interface GigabitEthernet1/0/16
switchport access vlan 2

Any thoughts?

[Reza Sharifi]

Could it that the devices connected to these ports go offline or to sleep?

Also, you may have a speed/duplex mismatch between the devices and the switch ports.

HTH

[hemantpatel]

Reza,

There is no device connected on the ports where we see  the line protocol bouncing.

[Reza Sharifi]

Hi,

As also Leo said, this is most likely a bug. I also recommend opening a ticket with Cisco as they may know the exact bug id.

HTH

[Leo Laohoo]

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@hemantpatel wrote:

I have seen log entries like following for the interfaces where no device is connected.

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This is "a very known issue" (aka "a bug") with IOS-XE.  It is not only affects 3650/3850 but all Catalyst 9k switches. 

There are several Bug IDs, however, the only workaround is a cold reboot (pull the power cable) of the switch or stack.

[hemantpatel]

@Leo Laohoo 

I had rebooted the switch with the reload command but it not did help. I will have to arrange physical help at data center to do the cold reboot.

I would appreciate if you can share bug-id or any phrase which I can use to find more details on the bug.

[Leo Laohoo]

I cannot find the Bug ID but these Bug IDs are very similar:  CSCvc26787 or CSCvg34034. 

NOTE:  
Due to the current "gone to the dogs" state of software quality control, I am refraining from my usual recommendation of "upgrade the firmware".