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Catalyst 3750 Metro Switch Command Reference
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Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
udld (interface configuration)
udld (interface configuration)
Use the
udld
interface configuration command to enable the UniDirectional Link Detection (UDLD) on
an individual interface or prevent a fiber-optic port from being enabled by the
udld
global configuration
command. Use the
no
form of this command to return to the
udld
global configuration command setting
or to disable UDLD if entered on a nonfiber-optic port.
udld port
{
aggressive
|
disable
}
no udld port
{
aggressive
|
disable
}
Syntax Description
Defaults
On fiber-optic ports, UDLD is not enabled, in aggressive mode, or disabled. For this reason, fiber-optic
ports enable UDLD according to the state of the
udld enable
or
udld aggressive
global configuration
command.
On nonfiber-optic ports, UDLD is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
A UDLD-capable interface cannot detect a unidirectional link if it is connected to a UDLD-incapable
interface of another switch.
UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLD
can detect unidirectional links due to misconnected ports on fiber-optic connections. In aggressive mode,
UDLD also can detect unidirectional links due to one-way traffic on fiber-optic and twisted-pair links
and due to misconnected ports on fiber-optic links. For information about normal and aggressive modes,
see the “Configuring UDLD” chapter in the software configuration guide for this release.
To enable UDLD in normal mode, use the
udld port
interface configuration command. To enable UDLD
in aggressive mode, use the
udld port
aggressive
interface configuration command.
Use the
no udld port
command on fiber-optic ports to return control of UDLD to the
udld enable
global
configuration command or to disable UDLD on nonfiber-optic ports.
Use the
udld port aggressive
command on fiber-optic ports to override the setting of the
udld enable
or
udld aggressive
global configuration command. Use the
no
form on fiber-optic ports to remove this
setting and to return control of UDLD enabling to the
udld
global configuration command or to disable
UDLD on nonfiber-optic ports.
The
disable
keyword is only supported on fiber-optic ports. Use the
no
form of this command to remove
this setting and to return control of UDLD to the
udld
global configuration command.
aggressive
Enable UDLD in aggressive mode on the specified interface.
disable
Disable UDLD on the specified interface. This keyword applies only to
fiber-optic ports.
Release
Modification
12.1(14)AX
This command was introduced.
