2-820Cisco Catalyst Blade Switch 3120 for HP Command ReferenceOL-12248-03Chapter 2 Cisco Catalyst Blade Switch 3120 for HP Cisco IOS Commandsudld portudld portUse the udld port interface configuration command on the switch stack or on a standalone switch to enablethe UniDirectional Link Detection (UDLD) on an individual interface or prevent a fiber-optic interfacefrom being enabled by the udld global configuration command. Use the no form of this command toreturn to the udld global configuration command setting or to disable UDLD if entered for anonfiber-optic port.udld port [aggressive]no udld port [aggressive]Syntax DescriptionDefaults On fiber-optic interfaces, UDLD is not enabled, not in aggressive mode, and not disabled. For thisreason, fiber-optic interfaces enable UDLD according to the state of the udld enable or udld aggressiveglobal configuration command.On nonfiber-optic interfaces, UDLD is disabled.Command Modes Interface configurationCommand HistoryUsage Guidelines A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port ofanother switch.UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLDdetects unidirectional links due to misconnected interfaces on fiber-optic connections. In aggressivemode, UDLD also detects unidirectional links due to one-way traffic on fiber-optic and twisted-pairlinks and due to misconnected interfaces on fiber-optic links. For information about normal andaggressive modes, see the “Configuring UDLD” chapter in the software configuration guide for thisrelease.To enable UDLD in normal mode, use the udld port interface configuration command. To enable UDLDin 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 globalconfiguration 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 enableor udld aggressive global configuration command. Use the no form on fiber-optic ports to remove thissetting and to return control of UDLD enabling to the udld global configuration command or to disableUDLD on nonfiber-optic ports.aggressive Enable UDLD in aggressive mode on the specified interface.Release Modification12.2(40)EX1 This command was introduced.
