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Catalyst 3750 SwitchSoftware Configuration Guide
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Chapter28 Configuring UDLD
Configuring UDLD
Default UDLD Configuration
Table28-1 shows the default UDLD configuration.
Configuration Guidelines
These are the UDLD configuration guidelines:
UDLD is not supported on ATM ports.
A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable
port of another switch.
When configuring the mode (normal or aggressive), make sure that the same mode is configured on
both sides of the link.
Caution Loop guard works only on point-to-point links. We recommend that each end of the link has a directly
connected device that is running STP.
Table28-1 Default UDLD Configuration
Feature Default Setting
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