Cisco Catalyst 3550 Series - Configuring UDLD

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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 23 Configuring UDLD
Configuring UDLD
Configuring UDLD
This section describes how to configure UDLD on your switch. It contains this configuration
information:
• Default UDLD Configuration, page 23-4
• Configuration Guidelines, page 23-4
• Enabling UDLD Globally, page 23-5
• Enabling UDLD on an Interface, page 23-5
• Resetting an Interface Shut Down by UDLD, page 23-6
Default UDLD Configuration
Table 23-1 shows the default UDLD configuration.
Configuration Guidelines
These are the UDLD configuration guidelines:
• UDLD is not supported on ATM interfaces.
• 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.
Table 23-1 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