Udld

xXErebuS

Hi guys,

I have a small (and I thought at the time quick) UDLD question that has been bugging me for awhile. I have been researching for awhile now about the default settings for UDLD per interface default settings. Everything, and I mean everything from 2000 - 2012 articles state that UDLD is ENABLED per interface by default on Fiber links. However, when I check this in a lab / at work on "real" equipment using show udld it states port enable status as disabled...


Interface Gi1/0/2
---
Port enable administrative configuration setting: Follows device default
Port enable operational state: Disabled
Current bidirectional state: Unknown

this is from a valid fiber link between two cisco switches (3750X & 2960S).


Thanks!

NetworkVeteran

xXErebuS wrote: »

Everything, and I mean everything from 2000 - 2012 articles state that UDLD is ENABLED per interface by default on Fiber links.this is from a valid fiber link between two cisco switches (3750X & 2960S)

When in doubt, check the docs. The docs are more reliable than random articles.

Catalyst 2960 and 2960-S Software Configuration Guide, 12.2(55)SE - Configuring UDLD* [Cisco Catalyst 2960 Series Switches] - Cisco Systems



UDLD global enable state

Globally disabled



UDLD per-port enable state for fiber-optic media

Disabled on all Ethernet fiber-optic ports



UDLD per-port enable state for twisted-pair (copper) media

Disabled on all Ethernet 10/100 and 1000BASE-TX ports



UDLD aggressive mode

Disabled




(When really in doubt, lab it up!)