UDLD/Loopguard

[Ibrahim Jamil]

Hi Netpro

UDLD and Loopguard should be configured and tuned  globaly in every switch in network (CORE/Access)am i right? what is the pros and cons for that

thanks

[Reza Sharifi]

Hi,

Have a look at this doc:

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094640.shtml#loop_guard_vs_uld

HTH

[Ibrahim Jamil]

Hi Riza

so  should I configure UDLD and Loopgurard in every switch in the network GLOBALY?

thanks

[Reza Sharifi]

Ibrahim,

UDLD  detects unidirectional failure when you using fiber ports and/or devices that are connected through media converters If you are using only copper in your environment, I really don't see a reason for deploying it.

Loop Guard is usually deployed on your uplink ports concerting access to distro or distro to core.

have a look at this doc for more info:

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094640.shtml

HTH

HTH

[Leo Laohoo]

so  should I configure UDLD and Loopgurard in every switch in the network GLOBALY?

I'd recommend you configure UDLD on all your fibre optic uplinks only.

If you have 6500 then think about using Fast UDLD.  Not sure if this feature is supported on the Sup6/Sup7 of the 4500.

[fb_webuser]

Depends a lot on the network. If you are running VSS on Cat6k, you do not want to enable STLG (Spanning-Tree Loop Guard) as it is a STP add-on, and VSS with MEC eliminates some STP usage. UDLD is recommended, especially for fiber infrastructure. Unidirectional links are considered to be a majority root cause of all bridging loops. PS: If you run 12.2(33)SXI4 or later, then you will get Fast UDLD, which is great for subsecond unidir. link detection for redundant and critical environments. Normally, if I had to choose between the two features, I would implement UDLD.

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Posted by WebUser Atle Ørn Hardarson