UDLD issue

Unanswered Question
Dec 5th, 2008


I have enabled udld globally. when issue the sh udld i am getting the following message on all interfaces(3750)

Interface Gi1/0/xx


Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

2) After use the below mentioned command.it is not showing in sh run config??pls let me know how i know that etherchannel guard is working or not?

spanning-tree etherchannel guard misconfig



I have this problem too.
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royalblues Sat, 12/06/2008 - 01:20

1. Are the ports connected via fiber? when you enable UDLD globally it is configured only on fiber ports by default and not on ethernet ports

Try configuring UDLD under each port and check

int g 1/0/x

udld port aggressive

2. The command spanning-tree etherchannel guard misconfig is enabled by default in the cisco IOS and hence is not shown in the running configuration. If you disable this using "no spanning-tree etherchannel guard misconfig " you should see it in your running config



glen.grant Sat, 12/06/2008 - 02:26

Just turning it globally will enable it on any fiber optic ports. If this is a copper port then you must also enable it individually on the copper ports as it is off by defualt on copper.

udld {aggressive | enable | message time message-timer-interval}

Specify the UDLD mode of operation:

•aggressive-Enables UDLD in aggressive mode on all fiber-optic ports.

•enable-Enables UDLD in normal mode on all fiber-optic ports on the switch. UDLD is disabled by default.

An individual interface configuration overrides the setting of the udld enable global configuration command.

For more information about aggressive and normal modes, see the "Modes of Operation" section.

•message time message-timer-interval-Configures the period of time between UDLD probe messages on ports that are in the advertisement phase and are detected to be bidirectional. The range is from 1 to 90 seconds.

Note The global UDLD setting is automatically applied to switches that join the switch stack.

Note This command affects fiber-optic ports only. Use the udld interface configuration command to enable UDLD on other port types. For more information, see the "Enabling UDLD on an Interface" section.


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