Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

err-disabled switch port

I have several ports on my network that I continue to see go into an err-disabled state when devices are connected to the network jack. I can fix these by doing a shut/no shut on the port, but I'm not sure what's causing this to happen?

No speed/duplex mismatches which has been the normal cause, so what else can cause this to happen? bad ethernet cables?

Thanks in advance.

/rls

6 REPLIES
Hall of Fame Super Silver

Re: err-disabled switch port

Hello Robert,

if you have logging enabled examine the log there should be a message for this.

possible causes include:

port security

STP BPDUguard

and probably also port flapping (this can be caused by cabling)

5 up/down in 1 sec can trigger port flapping.

if the port just disabled is x/y

use

sh log | inc x/y

Hope to help

Giuseppe

Community Member

Re: err-disabled switch port

I do see the port flapping error, but I'm not sure how that could be caused by cabling. Could you explain a little more?

Thanks.

/rls

Hall of Fame Super Silver

Re: err-disabled switch port

Hello Robert,

flapping is defined as frequent up/downs on the port for this I thought of a relationship with cabling issues (an intermittent link/wire in the RJ-45)

there is also an open issue about flapping on C2950 it is a bug.

We found it for frequent deregistration of VOIP phones caused by these up/downs

We tried last available IOS for C2950 but it didn't solve.

Hope to help

Giuseppe

Community Member

Re: err-disabled switch port

Thanks Giuseppe, so you think the cables could have some physical problems that cause the port to flap, and then go into err-disable mode? All of the switches are newer 3750s.

/rls

Hall of Fame Super Gold

Re: err-disabled switch port

UDLS Port Aggressive can also cause a port to go into err-disable.

Community Member

Re: err-disabled switch port

You can set the switch to automatically recover from an error disabled state, that way you don't have to waste your time logging in to the switch and shut/noshutting the port.

See here: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00806cd87b.shtml#topicsub1

1063
Views
10
Helpful
6
Replies
CreatePlease to create content