Cisco Catalyst 3650 Series User Manual

udld
To enable aggressive or normal mode in the UniDirectional Link Detection (UDLD) and to set the configurable
message timer time, use the udld command in global configuration mode. To disable aggressive or normal
mode UDLD on all fiber-optic ports, use the no form of the command.
udld {aggressive| enable| message time message-timer-interval}
no udld {aggressive| enable| message}
Syntax Description
Enables UDLD in aggressive mode on all fiber-optic interfaces.aggressive
Enables UDLD in normal mode on all fiber-optic interfaces.enable
Configures 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. The default is 15 seconds.
message time
message-timer-interval
Command Default
UDLD is disabled on all interfaces.
The message timer is set at 15 seconds.
Command Modes
Global configuration
Command History
ModificationRelease
This command was introduced.Cisco IOS XE 3.3SECisco IOS XE 3.3SE
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
Catalyst 2960-X Switch Layer 2 Configuration GuideCatalyst 2960-XR Switch Layer 2 Configuration
GuideLayer 2/3 Configuration Guide (Catalyst 3650 Switches).
If you change the message time between probe packets, you are making a compromise 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.
You can use these commands to reset an interface shut down by UDLD:
•
The udld reset privileged EXEC command to reset all interfaces shut down by UDLD.
Command Reference, Cisco IOS XE Everest 16.5.1a (Catalyst 3650 Switches)
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udld

Cisco Catalyst 3650 Series Specifications

General

Brand	Cisco
Model	Catalyst 3650 Series
Category	Switch
Language	English