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UDLD in cisco router

Unanswered Question
Jan 8th, 2014
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Hi all,


Do we have udld support in routers ? can someone pls guide me if we have this feature available on cisco routers ?                   

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Leo Laohoo Wed, 01/08/2014 - 01:24
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Do we have udld support in routers ? can someone pls guide me if we have this feature available on cisco routers ?

I don't think UDLD is supported in routers.

M. G. Wed, 01/08/2014 - 02:50
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UDLD is used to prevent STP loops, therefore it L2 protocol and it does not run on the L3 interfaces. If you have router with a switch ports on the router, then you might have it

Collin Clark Wed, 01/08/2014 - 09:17
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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. It is not used to prevent STP loops. It is supported on some of the etherswitch daughter cards. I don't have any fiber terminating on the chassis SFP ports so I'm not sure if it's supported there.

M. G. Wed, 01/08/2014 - 20:36
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This document explains how the Unidirectional Link Detection (UDLD) protocol can help to prevent forwarding loops and blackholing of traffic in switched networks.


Cisco

Regards,

Bhishma Khanna Wed, 01/08/2014 - 13:05
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Hi Jonn,


Just to give some more information about UDLD, whenever the switch detects a unidirectional link in the layer 2 LAN switching environment, it prefers to block the port completly(send it to err-disabled) rather than allowing the unidirectional flow of information. It has no use in the layer 3 environment.


Thanks.

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