H3C S5500-SI Series, Operation Manual

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1-8
To do… Use the command… Remarks
Enter system view system-view —
Enable global loopback
detection
loopback-detection enable
Required
Disabled by default
Configure the interval for port
loopback detection loopback-detection
interval-time time
Optional
30 seconds by default
Enter Ethernet interface view
interface interface-type
interface-number
—
Enable loopback detection on a
port
loopback-detection enable
Required
Disabled by default
Enable loopback detection
control on a trunk port or a
hybrid port
loopback-detection control
enable
Optional
Disabled by default
Enable loopback detection in all
the VLANs to which trunk or
hybrid ports belong
loopback-detection per-vlan
enable
Optional
Enabled only in the default
VLAN(s) with trunk port or
hybrid ports
z
Loopback detection on a given port is enabled only after the loopback-detection enable
command has been configured in both system view and the interface view of the port.
z
Loopback detection on all ports will be disabled after the configuration of the undo
loopback-detection enable command under system view.
Configuring the MDI Mode for an Ethernet Interface
10-Gigabit Ethernet ports and optical interfaces of SFP ports do not support this function.
Two types of Ethernet cables can be used to connect Ethernet devices: crossover cable and
straight-through cable. To accommodate these two types of cables, an Ethernet interface on a device
can operate in one of the following three Medium Dependent Interface (MDI) modes:
z
Across mode
z
Normal mode
z
Auto mode
An Ethernet interface is composed of eight pins. By default, each pin has its particular role. For example,
pin 1 and pin 2 are used for transmitting signals; pin 3 and pin 6 are used for receiving signals. You can
change the pin roles through setting the MDI mode. For an Ethernet interface in normal mode, the pin
roles are not changed. For an Ethernet interface in across mode, pin 1 and pin 2 are used for receiving