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

[gavin han]

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

[Markus Schwarz]

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]

why would trunk port go in "err-disabled"

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

[Markus Schwarz · Accepted solution]

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