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why would trunk port go in "err-disabled"? bpduguard isn't configured for this port.

Endorsed Question
Jan 16th, 2014
User Badges:

Hi,


why would trunk port go in "err-disabled"? bpduguard isn't configured for this port. following is the port info.



sw#sh run int TenGigabitEthernet3/2

Building configuration...


Current configuration : 203 bytes

!

interface TenGigabitEthernet3/2

switchport

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 35-37, 42, 43

switchport mode trunk

no ip address

end


sw#sh int TenGigabitEthernet3/2

TenGigabitEthernet3/2 is down, line protocol is down (err-disabled)

  Hardware is C6k 10000Mb 802.3, address is b0fa.eb0f.3e84 (bia b0fa.eb0f.3e84)

  Description: UCS

  MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,

     reliability 255/255, txload 1/255, rxload 1/255

Cisco Endorsed by shulipal
Markus Schwarz about 3 years 7 months ago

Hello Gavin,


Before you go out and start replacing things, please have a log in your buffer. Lets see if you have a log entry still on your device which provides a clue as to why this port went down . (I assume it went down recently)




show log | i TenGigabitEthernet3/2


Have a log if you see anything.


If you dont have a log entry, please go to the affected interface and perform a shut and after a few seconds a no shut to see if the port comes up again.


I assume it will stay up for a short period and then retrun into err-disable state based on your recent statement. In any case, i hope that the    show log | i TenGigabitEthernet3/2


Regards

marQes

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Markus Schwarz Thu, 01/16/2014 - 13:08
User Badges:

Hello Gavin,


I have come across this problem a few times in the past. Most of my problems were encountered during install activies as I kept constantly disconnecting and moving the GBICs in and out but of course there are other reasons:


There are various reasons for the interface to go into errdisable. The reason can be:


  • Duplex mismatch
  • Port channel misconfiguration
  • BPDU guard violation
  • UniDirectional Link Detection (UDLD) condition
  • Late-collision detection
  • Link-flap detection
  • Security violation
  • Port Aggregation Protocol (PAgP) flap
  • Layer 2 Tunneling Protocol (L2TP) guard
  • DHCP snooping rate-limit
  • Incorrect GBIC / Small Form-Factor Pluggable (SFP) module or cable
  • Address Resolution Protocol (ARP) inspection
  • Inline power



The most common reason (for me anyhow) was donw to cable and GBIC so I assume this would be the best place to start.


Hope that helps


Regads

marQes

Leo Laohoo Thu, 01/16/2014 - 13:09
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why would trunk port go in "err-disabled"

The answer to this question is the command "sh interface status err".

Markus Schwarz Thu, 01/16/2014 - 13:16
User Badges:

Hello Gavin,


Before you go out and start replacing things, please have a log in your buffer. Lets see if you have a log entry still on your device which provides a clue as to why this port went down . (I assume it went down recently)




show log | i TenGigabitEthernet3/2


Have a log if you see anything.


If you dont have a log entry, please go to the affected interface and perform a shut and after a few seconds a no shut to see if the port comes up again.


I assume it will stay up for a short period and then retrun into err-disable state based on your recent statement. In any case, i hope that the    show log | i TenGigabitEthernet3/2


Regards

marQes

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