3Com Switch 8800 Advanced Software V5 Configuration Guide

Ethernet Interface Configuration 57
Configuring the
Suppression Time of
Physical-Link-State
Change on an Ethernet
Interface
An Ethernet interface operates in one of the two physical link states: up or down.
During the suppression time, physical-link-state changes will not be propagated to
the system. Only after the suppression time has elapsed will the system be notified
of the physical-link-state changes by the physical layer. This functionality reduces
the extra overhead occurred due to frequent physical-link-state changes within a
short period of time.
Follow these steps to configure the up/down suppression time on an Ethernet
Interface:
Configuring Loopback
Testing on an Ethernet
Interface
You can enable loopback testing to check whether the Ethernet interface
functions properly. Note that no data packets can be forwarded during the testing.
Loopback testing falls into the following two categories:
■ Internal loopback testing: a loopback testing carried out within the device, if
data packets sent from an Ethernet interface can be received by the same
interface, the internal loopback testing is successful indicating that the
interface is functioning properly.
■ External loopback testing: a loopback plug needs to be plugged into an
Ethernet interface, if data packets sent from the interface is received by the
same interface through the loopback plug, the external loopback testing is
successful indicating that the interface is functioning properly.
Follow these steps to enable Ethernet interface loopback testing:
n
■ Currently, Switch 8800s do not support the external loopback testing.
■ Internal loopback testing can only be enabled on interfaces in down state. That
is, it is unavailable to interfaces that are shut down manually.
■ The speed, duplex, mdi, and shutdown commands are not applicable during
a loopback testing.
■ With the loopback testing enabled, the Ethernet interface works in the full
duplex mode at highest speed. With the loopback testing enabled, the original
configurations will be restored.
To do... Use the command... Remarks
Enter system view system-view -
Enter Ethernet interface view interface interface-type
interface-number
-
Configure the up/down
suppression time of
physical-link-state changes
link-delay delay-time Required
Defaults to 1 second.
To do... Use the command... Remarks
Enter system view system-view -
Enter Ethernet interface view interface interface-type
interface-number
-
Enable loopback testing loopback { external |
internal }
Optional
Disabled by default.