Cisco ME 3600X, Command Reference Manual

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Cisco ME 3800X and ME 3600X Switch Command Reference
OL-28238-01
Chapter
udld port
udld port
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 udld port command in
interface configuration mode. To return to the udld global configuration command setting or to disable
UDLD if entered for a nonfiber-optic port, use the no form of this command.
udld port [ aggressive | disable ]
no udld port [ aggressive | disable ]
Syntax Description
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
Usage Guidelines
A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of
another switch. If the port is a user network interface (UNI) or enhanced network interface (ENI), you
must use the
no shutdown interface configuration command to enable it before using the udld port
command. UNIs and ENIs are disabled by default. Network node interfaces (NNIs) are enabled by
default.
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.
aggressive Enables UDLD in aggressive mode on the specified interface.
disable Disables UDLD on this interface despite the global UDLD setting.
Release Modification
12.2(52EY This command was introduced.