2-878
Catalyst 3750 Switch Command Reference
OL-8552-07
Chapter 2 Catalyst 3750 Switch Cisco IOS Commands
udld
udld
Use the
udld
global configuration command to enable aggressive or normal mode in the UniDirectional
Link Detection (UDLD) and to set the configurable message timer time. Use the
no
form of the
command to disable aggressive or normal mode UDLD on all fiber-optic ports.
udld
{
aggressive
|
enable
|
message time
message-timer-interval
}
no udld
{
aggressive
|
enable
|
message
}
Syntax Description
Defaults
UDLD is disabled on all interfaces.
The message timer is set at 60 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
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 “Understanding UDLD” section in the software configuration guide for this
release.
If you change the message time between probe packets, you are making a trade-off between the detection
speed and the CPU load. By decreasing the time, you can make the detection-response faster but increase
the load on the CPU.
This command affects fiber-optic interfaces only. Use the
udld
interface configuration command to
enable UDLD on other interface types.
aggressive
Enable UDLD in aggressive mode on all fiber-optic interfaces.
enable
Enable UDLD in normal mode on all fiber-optic interfaces.
message time
message-timer-interval
Configure the period of time between UDLD probe messages on ports that
are in the advertisement phase and are determined to be bidirectional. The
range is 1 to 90 seconds.
Release
Modification
12.1(11)AX
This command was introduced.
12.2(25)SEC
The range for the
message-timer-interval
was changed from 7 to 90 seconds
to 1 to 90 seconds.
