Udld Port - Cisco Catalyst 2950 Command Reference Manual

udld port

udld port
Use the udld port interface configuration command to enable UniDirectional Link Detection (UDLD)
on an individual interface or to prevent a fiber-optic interface 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 for a nonfiber-optic port.
Syntax Description aggressive
Defaults
On fiber-optic interfaces, UDLD is not enabled, not in aggressive mode, and not disabled. For this
reason, fiber-optic interfaces enable UDLD according to the state of the udld enable or udld aggressive
global configuration command.
On nonfiber-optic interfaces, UDLD is disabled.
Command Modes
Interface configuration
Command History Release
12.0(5.2)WC(1)
12.1(6)EA2
12.1(14)EA1
12.1(20)EA2
Usage Guidelines UDLD is supported on fiber- and copper-based Ethernet ports.
A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of
another switch.
This setting overrides the global UDLD configuration on the switch.
UDLD supports two modes of operation: normal mode (the default) and aggressive mode. In normal
mode, UDLD detects unidirectional links due to misconnected interfaces on fiber-optic connections. In
aggressive mode, UDLD also detects unidirectional links due to one-way traffic on fiber-optic and
twisted-pair links and due to misconnected interfaces 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.
Catalyst 2950 and Catalyst 2955 Switch Command Reference
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udld port [aggressive]
no udld port [aggressive]
(Optional) Enable UDLD in aggressive mode on the specified interface.
Modification
This command was introduced.
The aggressive keyword was added.
The port keyword was added. The enable keyword was removed.
The disable keyword was removed.
Chapter 2 Catalyst 2950 and 2955 Cisco IOS Commands
OL-10102-01