3
Configuring physical state change suppression on an
Ethernet interface
IMPORTANT:
Do not configure physical state change suppression on an Ethernet interface that has RRPP, MSTP,
or Smart Link enabled.
The physical link state of an Ethernet interface is either up or down. Each time the physical link of a
port comes up or goes down, the interface immediately reports the change to the CPU. The CPU
then performs the following operations:
•
Notifies the upper-layer protocol modules (such as routing and forwarding modules) of the
change for guiding packet forwarding.
•
Automatically generates traps and logs, informing the user to take the correct actions.
To prevent frequent physical link flapping from affecting system performance, configure physical
state change suppression to suppress the reporting of physical link state changes. The system
reports physical layer changes only when the suppression interval expires.
When the
link-delay
delay-time
command is configured:
•
The link-down event is not reported to the CPU unless the interface is still down when the
suppression interval (
delay-time
) expires.
•
The link-up event is immediately reported.
When the
link-delay
delay-time mode up
command is configured:
•
The link-up event is not reported to the CPU unless the interface is still up when the
suppression interval (
delay-time
) expires.
•
The link-down event is immediately reported.
When the
link-delay
delay-time mode updown
command is configured:
•
The link-down event is not reported to the CPU unless the interface is still down when the
suppression interval (
delay-time
) expires.
•
The link-up event is not reported to the CPU unless the interface is still up when the
suppression interval (
delay-time
) expires.
To configure physical state change suppression on an Ethernet interface:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Ethernet
interface view.
interface
interface-type
interface-number
N/A
3.
Configure physical
state change
suppression on the
interface.
link-delay
[
msec
]
delay-time
[
mode
{
up
|
updown
}]
By default, the link-down or link-up event is
immediately reported to the CPU.
If you configure this command multiple times on
an Ethernet interface, the most recent
configuration takes effect.
Performing a loopback test on an Ethernet interface
If an Ethernet interface does not work correctly, you can perform a loopback test on it to identify the
problem. An Ethernet interface in a loopback test does not forward data traffic.
