Error-disabled with UP link of Cisco 2960

[HCL Support]

Hi,

We have got error-disabled on the Up Link of switch cisco 2960 at customer site but as per config this port is somply trunk port.

Error logs for this issue is below,

Log Buffer (4096 bytes):

_DISABLE: loopback error detected on Gi0/1, putting Gi0/1 in err-disable state

Also attaching show tech-support and show logging for this switch,

Regards,

Ashutosh

[Leo Laohoo]

Are you sure this is the correct switch? 

[HCL Support]

Hi,

Yes,

These are logs of the switch faced issue.

Regards,

Ashutosh

[JohnTylerPearce]

I've never personally seen this issue up close and personal, but I have read about it a few times. This appears to

be when an ethernet keepalive is being sent out of an interface and is also received on the same interface it

sent it out on. It sounds like a logical Spanning Tree loop. When I read about this a few months ago, most of the

fixes were to upgrade the IOS to a certain version and or disable ethernet keepalives on the specified port.

[Leo Laohoo]

Can you please post the "sh tech" of the other switch then?

[HCL Support]

Hi,

Find attached here show tech-support of the switch connected through this UP Link port G0/1 of reported switch.

Regards,

Ashutosh