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dm2020
Beginner

UDLD on routed ports

Hi All,

 

I have been reading up on UDLD and one of the primary use cases of using this protocol is to prevent L2 loops if a link becomes unidirectional. Does UDLD have any advantages on a routed ports or should this used on L2 ports only?

 

Thanks

4 REPLIES 4
balaji.bandi
VIP Expert

UDLD on L2 port,  More information can be found here :

 

https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/10591-77.html



BB


*** Rate All Helpful Responses ***

Hi

 

Thanks for the reply.

 

I have checked our switches and UDLD is enabled on our L3 ports with full bidirectional neighbor states so it does seems that IOS-XE allows UDLD on routed ports. Are you saying that there is no benefit to this and the benefit is on L2 ports only?

 

Thank you

 

 

Reza Sharifi
Hall of Fame Expert

Hi,

UDLD is a layer 2 protocol to detect physical faults (layer-1). So, I don't see why it can't be used for both l2 and l3 links..

 

HTH

Leo Laohoo
VIP Community Legend


@dm2020 wrote:

Does UDLD have any advantages on a routed ports or should this used on L2 ports only?


Is UDLD auto-recovery going to be enabled?  
IF it is, don't enable UDLD:  Auto-recovery simply defeats the purpose of UDLD plus, on a routed port(s), may cause high CPU (if the port goes up/down very, very often) which will ultimately lead to a crash.