3Com 3C13636 Configuration Manual page 258

3Com Router 3000 Ethernet Family
Configuration Guide
Table 2-6 Enable or disable local loopback
Enable local loopback
Disable local loopback
By default, local loop is disabled.
Note:
Ethernet interfaces will work in full-duplex mode when loopback is enabled.
If the operating speed is 1000Mbps or negotiation, the system will force to convert
it to 100Mbps when loopback is enabled. In addition, it will restore the original
setting when loopback is disabled.
When loopback is enabled, you can change the GE operating speed to 10Mbps or
100Mbps. If the new speed is different from the current speed, it starts loopback in
the new speed and saves the new configuration. In other cases (GE operating
speed is changed to 1000Mbps or negotiation, or operating mode is changed to
half-duplex mode), the new configuration is saved. It disables loopback and starts to
work in the new mode.
VII. Configuring Flow Control on an Ethernet Interface
Perform the following configuration in Ethernet interface view.
Table 2-7 Configure flow control on the Ethernet interface
Enable flow control on the Ethernet interface.
Restore the default.
By default, flow control is disabled. Flow control can take effective only when it is
enabled at both ends.
When flow control is enabled, the system cannot enter normal UP state if negotiation
fails. If flow control is enabled on the local interface, you are recommended to execute
the shutdown command and then the undo shutdown command to restart the
interface when the configuration of the peer end changes, to keep the flow control
mode the same on both ends.
Operation
Operation
3Com Corporation
2-5
Chapter 2 LAN Interface Configuration
Command
loopback
undo loopback
Command
flow-control
undo flow-control