R3303-HP HSR6800 Routers Interface Configuration Guide

14
Step Command Remarks
7. Enable loopback detection
control on a trunk port or a
hybrid port.
loopback-detection control enable
Optional.
By default, loopback detection
control is disabled.
8. Enable loopback detection in
all VLANs on the trunk or
hybrid port.
loopback-detection per-vlan
enable
Optional.
By default, a trunk or hybrid port
performs loopback detection only
in its PVID.
9. Set the protective action to
take on the interface when a
loop is detected.
loopback-detection action
{ no-learning | semi-block |
shutdown }
Optional.
By default, when a loop is detected
on an interface, the interface does
not forward any data packet.
With the shutdown keyword
specified, the looped port is
automatically shut down and its
physical state changes to Loop
down. After the loop is removed,
use the undo shutdown command
on the port to recover its
forwarding capability.
Setting the MDI mode of an Ethernet interface
IMPORTANT:
Fiber ports do not support the MDI mode setting.
You can use both crossover and straight-through Ethernet cables to connect copper Ethernet interfaces.
To accommodate these types of cables, a copper Ethernet interface can operate in one of the following
Medium Dependent Interface (MDI) modes:
• Across mode
• Normal mode
• Auto mode
A copper Ethernet interface uses an RJ-45 connector, which comprises eight pins, each of which plays a
dedicated role. For example, pins 1 and 2 transmit signals, and pins 3 and 6 receive signals. The pin
role varies by the MDI modes as follows:
• In normal mode, pins 1 and 2 are transmit pins, and pins 3 and 6 are receive pins.
• In across mode, pins 1 and 2 are receive pins, and pins 3 and 6 are transmit pins.
• In auto mode, the interface negotiates pin roles with its peer.
To enable the interface to communicate with its peer, make sure its transmit pins are connected to the
remote receive pins. If the interface can detect the connection cable type, set the interface in auto MDI
mode. If not, set its MDI mode by using the following guidelines:
• When a straight-through cable is used, set the interface to operate in the MDI mode different than
its peer.