Udld Port - Cisco Catalyst 2960 Command Reference Manual

udld port

udld port
Use the udld port interface configuration command to enable the UniDirectional Link Detection
(UDLD) on an individual interface or 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
12.2(25)FX
Usage Guidelines A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of
another switch.
UDLD supports two modes of operation: normal (the default) and aggressive. 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.
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.
Catalyst 2960 Switch Command Reference
2-581
udld port [aggressive]
no udld port [aggressive]
Enable UDLD in aggressive mode on the specified interface.
Modification
This command was introduced.
Chapter 2 Catalyst 2960 Switch Cisco IOS Commands
OL-8604-04