Loopback-Detection Interval-Time - H3C S5120-EI Series Command Reference Manual

Description
Use the loopback-detection enable command to enable loopback detection globally in system view or on
ports in Ethernet interface or port group view. To use loopback detection on an Ethernet port, you must
enable the function both globally and on the port.
Use the undo loopback-detection enable command to disable loopback detection globally or on ports.
The undo loopback-detection enable command in system view disables loopback detection on all ports.
By default, loopback detection is disabled on all Ethernet ports.
If a port receives a packet that it sent out, a loop has occurred. Loops may cause broadcast storms,
degrading network performance. You can use loopback detection to detect loops on a port and
configure the protective action (shut down the port, for example) to take on the port when a loop is
detected.
In addition to the configured protective action, the switch also performs other actions to alleviate the
impact of the loop condition. For more information,
Table 10 Actions to take upon detection of a loop condition
Port type
Access port
Hybrid or trunk port
Related commands: loopback-detection control enable.
Examples
# Enable loopback detection on GigabitEthernet 1/0/1.
<Sysname> system-view
[Sysname] loopback-detection enable
[Sysname] interface gigabitethernet 1/0/1
[Sysname-GigabitEthernet1/0/1] loopback-detection enable

loopback-detection interval-time

Syntax
loopback-detection interval-time time
undo loopback-detection interval-time
Actions
No protective action is configured
•
Put the port in controlled mode. The
port discards all incoming packets,
but still forwards outgoing traffic.
•
Create traps.
•
Delete all MAC address entries of the
port.
•
Create traps.
•
If loopback detection control is
enabled, set the port in controlled
mode. The port discards all
incoming packets, but still forwards
outgoing packets.
•
Delete all MAC address entries of the
port.
29
seeTable 10.
A protective action is configured
•
Perform the configured protective
action.
•
Create traps and log messages.
•
Delete all MAC address entries of the
port.
•
Create traps and log messages.
•
If loopback detection control is
enabled, take the configured protective
action on the port.
•
Delete all MAC address entries of the
port.