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New Member

UDLD Problem after switch reload

I have the following problem with

Situation:

- 2x 3750G-12S Distribution-Switches (DS) and several 3560/2960 Access-Switches (AS)

- redundant Fiber optic uplinks between AS and DS

- Cross-Stack Etherchannel config on all uplinks

- UDLD aggressive mode configured on all uplinks

Problem:

- when I reload the DS and the switch comes up again, I've lost the connection with several (not all) AS

- looking at the AS log I found the following error message: "%UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi0/1, aggressive mode failure detected"

Cause:

- in the log of the AS I don't see intf Gi0/1 go down during the reload of the DS

- this means the DS didn't shuts down all its ports during the reload

- but this also means that UDLD on AS didn't know about DS reload, and therefore didn't resets counters

Workaroud/Solution

- I'm now configuring errdisable recovery on all AS

So I'm forced to configure errdisable recovery, even if I don't want.

Any other solutions/workaround?

For Cisco guys: what do you think about my case: it has to be considered a Cisco bug?

Regards, Gio.

Everyone's tags (3)
3 REPLIES
Cisco Employee

Re: UDLD Problem after switch reload

Hello,

How are the DS and AS switches connected? Do you have any patch panel or

signal booster in between? When you reload the switches, the switch will

turn-off all the ports for a short duration. You can see that in the console

logs when the switch was rebooting. So, if in your case it is not happening,

it could be a hardware issue or a software issue. Can you remove one of the

connections from the DS and see if the corresponding AS reports link down?

Regards,

NT

New Member

Re: UDLD Problem after switch reload

Hi Nagaraja,

yesterday evening I reloaded two more Distribution Stacks (upgrade from 12.2(50)SE3 to 12.2(55)SE due to a SW Bug) and I experienced again the same problem.

Here below an example of the logging on the AS:

000329: Sep 13 14:43:08: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi0/1, aggressive mode

failure detected

000330: Sep 13 14:43:08: %PM-4-ERR_DISABLE: udld error detected on Gi0/1, putting Gi0/1 in err-disable state

000331: Sep 13 14:43:09: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed

state to down

000332: Sep 13 14:43:10: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down

000333: Sep 13 14:43:11: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi0/2, aggressive mode

failure detected

000334: Sep 13 14:43:11: %PM-4-ERR_DISABLE: udld error detected on Gi0/2, putting Gi0/2 in err-disable state

000335: Sep 13 14:43:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed

state to down

Note: no "interface GigabitEthernet x/y changed to state down" message before the errdisable message, even if the device on the other side of the uplink was reloaded.

I'm sure that I have no active components between the AS and the DS.

Attention: I reviewed all logs of my lasts reload activities and one interesting things comes out: each time I experienced the UDLD Errdisable problem it was on Gigabit COPPER uplinks.

So it seems the 3750 Distribution switches didn't put in down state the Gigabit Copper SFP modules ...

New Member

UDLD Problem after switch reload

I had the same problem as you tonight while upgrading a WS-C2960-24TT-L. When it rebooted, the neighbour-switch put the 10/100/1000BaseTX interface in err-disable state.

Here's the log from the neighbouring WS-C2960-24TT-L:

Apr 30 00:41:33.756 UTC: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi0/2, aggressive mode failure detected

Apr 30 00:41:33.756 UTC: %PM-4-ERR_DISABLE: udld error detected on Gi0/2, putting Gi0/2 in err-disable state

Apr 30 00:41:34.763 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to down

Apr 30 00:41:35.778 UTC: %LINK-3-UPDOWN: Interface GigabitEthernet0/2, changed state to down

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