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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 28 Configuring UDLD
Default UDLD Configuration
Default UDLD Configuration
Table 28-1 shows the UDLD default configuration.
Configuring UDLD on the Switch
The following sections describe how to configure UDLD:
• Fast UDLD Guidelines and Restrictions, page 28-4
• Enabling UDLD Globally, page 28-5
• Enabling UDLD on Individual Interfaces, page 28-6
• Disabling UDLD on Individual Interfaces, page 28-7
• Disabling UDLD on a Fiber-Optic Interface, page 28-7
• Configuring a UDLD Probe Message Interval Globally, page 28-8
• Resetting Disabled LAN Interfaces, page 28-8
Fast UDLD Guidelines and Restrictions
When using (or configuring) Fast UDLD, consider these guidelines and restrictions:
• Fast UDLD is disabled by default.
• Configure fast UDLD only on point-to-point links between network devices that support fast
UDLD.
• You can configure fast UDLD in either normal or aggressive mode.
• Do not enter the link debounce command on fast UDLD ports.
• Configure fast UDLD on at least two links between each connected network device. This reduces
the number of link disablements due to false positives.
• Fast UDLD does not report a unidirectional link if the same error occurs simultaneously on more
than one link to the same neighbor device.
• Fast UDLD is supported on a limited number of ports.
Table 28-1 UDLD Default Configuration
Feature Default Status
UDLD global enable state Globally disabled.
UDLD per-interface enable state for fiber-optic media Enabled 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.
Fast UDLD per-interface enable state. Disabled on all interfaces.
