H3C Technologies H3C SR8800 - Manual (Page 13)

6
Configuring physical state change suppression on an Ethernet
interface
The physical link state of an Ethernet interface is either up or down. Each time the physical link of a port
goes up or comes down, the physical layer reports the change to the upper layers, and the upper layers
handle the change, resulting in increased overhead.
To prevent physical link flapping from affecting system performance, configure physical state change
suppression to delay the reporting of physical link state changes. The physical layer reports the changes
only when the delay 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. Set the physical state change
suppression interval.
link-delay delay-time The default setting is one second.
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. Loopback testing has the following types:
• Internal loopback testing—Packets sent from the interface are internally looped back to the
interface without being sent onto the line. If the internal operation of the interface is normal, the
interface should be able to receive the self-sent packets.
• External loopback testing—To perform external loopback testing on an Ethernet interface, connect
a loopback plug to the Ethernet interface. The device sends test packets out the interface, which are
expected to loop over the plug and back to the interface. If the interface fails to receive any test
packet, the hardware of the interface is faulty.
An Ethernet interface in a loopback test does not forward data traffic.
To enable loopback testing 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. Enable loopback testing. loopback { external | internal }
Optional.
By default, loopback test is
disabled.