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Is udld actually needed?

Unanswered Question
Nov 14th, 2006
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Hello All


I wonder if udld on fibre links is really needed to be enabled or not.

Are there actually any benefits of enabling it in a completely fine running network?

We only use Cisco Switches here, from around 6 different series.


Thanks,

pato

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ankbhasi Tue, 11/14/2006 - 07:34
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Hi Pato,


Network is running fine and cross your finger it keep working fine but you never know when problem can come and cause some major issues.


UDLD is a Layer 2 protocol that enables devices connected through fiber-optic or twisted-pair Ethernet cables to monitor the physical configuration of the cables and detect when a unidirectional link exists. All connected devices must support UDLD for the protocol to successfully identify and disable unidirectional links. When UDLD detects a unidirectional link, it disables the affected port and alerts you. Unidirectional links can cause a variety of problems, including spanning-tree topology loops.


So no problem in enabling UDLD.


Have a look at this link for more details


http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12225see/scg/swudld.htm


HTH


Ankur

patoberli Tue, 11/14/2006 - 07:51
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Thanks for the answers.

One more question, if I enable UDLD on one switch, would that cause any spanning-tree issues till I'd have it enabled on the connected switches?

Or can I simply enable it globally and nothing will happen?


Thanks,

pato

ankbhasi Tue, 11/14/2006 - 08:26
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  • Cisco Employee,

Hi Pato,


You will definetely not be able to implement this on all the switches at a same time so you can enable it on one switch and then start doing it on neighbor switches.


I will always recommed you when you raise a change request to implement this arrange some time for the same and also try to do it when there are minimal users.


Also recommend you to have a look at the link before implementing.


HTH


Ankur


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