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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 22 Configuring UDLD
Configuring UDLD
Default UDLD Configuration
Table 22-1 shows the default UDLD configuration.
Configuration Guidelines
These are the UDLD configuration guidelines:
• A UDLD-capable interface also 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.
Ta b l e 22-1 Default UDLD Configuration
Feature Default Setting
UDLD global enable state Globally disabled
UDLD per-interface enable state for fiber-optic media Disabled on all Ethernet fiber-optic interfaces
UDLD per-interface enable state for twisted-pair (copper)
media
Disabled on all Ethernet 10/100 and 1000BASE-TX
interfaces
UDLD aggressive mode Disabled
