configure ports link-flap-detection interval threshold disable-time

configure ports [port_list | all] link-flap-detection [{interval [interval | indefinitely]} {threshold threshold} {disable-time [disable_time | until-cleared]}]


Sets interval, threshold (maximum number of link down events), and disable time values for link-flap detection.

Syntax Description

ports Physical ports.
port_list List of ports to activate link-flap detection upon.
all Sets link-flap detection characteristics on all ports in the system.
interval Sets time interval for collecting link-flap events.
interval Interval value in seconds. Default is 5 seconds. Range is 1 second to indefinitely.
indefinitely Accumulate link-flap instances forever.
threshold Sets number of link-flap events tolerated before action is taken.
threshold Threshold value. Default is 10. Minimum threshold is 1; maximum threshold value depends on the link-flap detection configured link-flap interval and the link scan interval.
disable-time Sets time period a port remains disabled after detecting excessive link flapping.
disable_time Disable time in seconds. Default is 300 seconds. Range is 1 seconds to until enabled by user.
until-cleared Port remains down until you issue clear ports [port_list | all] link-flap-detection status command.


These options have the following default values:
Option Default Value
Interval 5 seconds
Threshold 10 link flaps
Disable time 300 seconds


If the default link-scan interval is 50 ms, then in 1 second, a maximum of 20 link state transitions (up or down) and 10 link down transitions can be detected. Assuming the link-flap interval is set to 5, the maximum link-flap threshold is 10 * 5 = 50. Maximum threshold for interval of 10 seconds appears in the output of the show ports all link-flap configuration command.

For example, the following sequence of commands generates an error message:
configure ports 7 link-flap-detection interval 5
configure ports 7 link-flap-detection threshold 200
Error: Maximum threshold is 100 for port 7 for current 
configuration of link-flap interval of 5 seconds.
Similarly, if the current threshold is 50, default link-scan interval is 50 ms, and the interval is changed to 4 seconds, then an error message appears:
configure ports 7 link-flap-detection threshold 100
configure ports 7 link-flap-detection interval 2
Error: Current threshold of 100 for port 7 is invalid with
new interval value of 2 seconds. Threshold must be less 
than 40 for interval to be 2 seconds.


The following example sets the threshold value to 15 link flaps that can be accumulated in an infinite interval for all ports.

configure ports all link-flap-detection interval indefinitely threshold 15


This command was first available in ExtremeXOS release 22.1.

Platform Availability

This command is available on ExtremeSwitching X435, X440-G2, X450-G2, X460-G2, X465, X590, X620, X670-G2, X690, X695, X870, 5320, 5420, and 5520 series switches.