H3C Technologies H3C S3100 Series Switches - Manual (Page 148)

1-7
z external: Performs external loop test. In the external loop test, self-loop headers must be used on
the port of the switch ( for 100M port, the self-loop headers are made from four cores of the 8-core
cables, for 1000M port, the self-loop header are made from eight cores of the 8-core cables, then
the packets forwarded by the port will be received by itself.). The external loop test can locate the
hardware failures on the port.
z internal: Performs internal loop test. In the internal loop test, self loop is established in the
switching chip to locate the chip failure which is related to the port.
Note that:
z After you use the shutdown command on a port, the port cannot run loopback test.
z You cannot use the speed, duplex, mdi and shutdown commands on the ports running loopback
test.
z Some ports do not support loopback test, and corresponding prompts will be given when you
perform loopback test on them.
Configuring a Port Group
To make the configuration task easier for users, certain devices allow users to configure on a single port
as well as on multiple ports in a port group. In port group view, the user only needs to input the
configuration command once on one port and that configuration will apply to all ports in the port group.
This effectively reduces redundant configurations.
A Port group could be manually created by users. Multiple Ethernet ports can be added to the same port
group but one Ethernet port can only be added to one port group.
Table 1-7 Configuring a Port Group
Operation Command Remarks
Enter system view system-view —
Create a port group or enter the specified port group
view
port-group group-id Required
Add an Ethernet port to a specified port group port interface-list Required
z Only S3100-EI Series Ethernet Switches support Port Group feature.
z A port can not be added to a port group if it has been added to an aggregation group, and vice
versa.