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UDLD aggressive configuration

                   We have an issue/query with UDLD operations across a MAN.  UDLD aggressive works as it should to error disable the ports on one of the etherchannel links where there is a problem in the Telco's MAN. However if we then manually bring these ports up before the link problems are fixed the switch ports on both ends of the faulty link stay up causing links problems between the two sites across the MAN. 

What I dont understand is why dosent UDLD put the ports back into error disable again. For this reason using the errdisable recovery command is unfortunatley out of the question for our use.   Is this an issue on all IOS versions and all models of cisco switches ?

We have a stack of 3750's on each side of the MAN link. Also had similar problems between a stack of 3750's and 6509 VS's across another MAN link as well.

Has anyone else come across this ?

Regards

Rob

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UDLD aggressive configuration

What I dont understand is why dosent UDLD put the ports back into error disable again.

There is a global command to re-enable err-disabled port after 30 seconds but I wouldn't recommend using it. 

If ports go into err-disable due to UDLD then it gives you notice.  If you automatically re-enable the port you wouldn't know that you've got a potential layer 1 issue.  Now if you do routing and this port goes up and down like-there's-no-tomorrow your router is going to go mental. 

New Member

UDLD aggressive configuration

Thank for your replay Leo, however my query is if UDLD is still running on both ends of the links why dosen't both the ports go back into error disable.   Is it because the physical link is now down so the ports on each end never gets the packets to bring up the ' UDLD link ' ?

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