H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 15)

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the physical link is still down when the timer expires, the interface reports the link-down event to the upper
layers.
Link-up event suppression enables an interface to suppress link-up events and start a delay timer each
time the physical link goes up. During this delay, the interface does not report the link-up event, and the
display interface brief or display interface command displays the interface state as DOWN. If the
physical link is still up when the timer expires, the interface reports the link-up event to the upper layers.
Configuring link-down event 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. Set a link-down event
suppression interval.
link-delay delay-time
Link-down event suppression is
disabled by default.
The link-delay command and the
link-delay mode up command
supersede each other. The last
command you configure takes effect.
Configuring link-up event 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. Set a link-up event suppression
interval.
link-delay delay-time mode up
Link-up event suppression is disabled
by default.
The link-delay mode up command and
the link-delay command supersede
each other. The last command that you
configure takes effect.
Configuring loopback testing on an Ethernet interface
If an Ethernet interface does not work normally, you can enable loopback testing on it to identify the
problem. An Ethernet interface in a loopback test does not forward data traffic.
Loopback testing has the following types:
• Internal loopback testing—Tests all on-chip functions related to Ethernet interfaces.
• External loopback testing—Tests hardware of Ethernet interfaces. To perform external loopback
testing on an Ethernet interface, connect a loopback plug to the Ethernet interface. The device sends
test packets out of the interface, which are expected to loop over the plug and back to the interface.
If the interface fails to receive any test packets, the hardware of the interface is faulty.
Configuration restrictions and guidelines
• On an interface administratively shut down, you cannot perform internal or external loopback
testing.