Enables and/or enters unidirectional link detection (UDLD) protocol configuration mode.
This protocol is disabled by default.
Global configuration mode
UDLD detects and blocks a physical link that becomes unidirectional. A unidirectional link can cause traffic in a network to loop endlessly. When the link becomes bidirectional again, UDLD unblocks the link.
This protocol applies only to physical ports. In addition to running this command, you must also enable each desired port for UDLD in interface subconfiguration mode.
Use the no protocol udld command to disable the UDLD protocol and revert all UDLD configuration to defaults.
To enable the unidirectional link detection (UDLD) protocol:
device# configure terminal device(config)# protocol udld