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- Table of Contents
-
- 04-Layer 2 - LAN Switching Command Reference
- 00-Preface
- 01-VLAN Commands
- 02-MAC Address Table Commands
- 03-Spanning Tree Commands
- 04-Ethernet Link Aggregation Commands
- 05-Port Isolation Commands
- 06-QinQ Commands
- 07-VLAN Mapping Commands
- 08-BPDU Tunneling Commands
- 09-GVRP Commands
- 10-Loopback Detection Commands
- 11-VLAN Termination Commands
- 12-MAC-in-MAC Commands
- 13-LLDP Commands
- 14-MVRP Commands
- Related Documents
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| Title | Size | Download |
|---|---|---|
| 10-Loopback Detection Commands | 83.67 KB |
display loopback-detection
Syntax
display loopback-detection [ | { begin | exclude | include } regular-expression ]
View
Any view
Default level
1: Monitor level
Parameters
|: Filters command output by specifying a regular expression. For more information about regular expressions, see Fundamentals Configuration Guide.
begin: Displays the first line that matches the specified regular expression and all lines that follow.
exclude: Displays all lines that do not match the specified regular expression.
include: Displays all lines that match the specified regular expression.
regular-expression: Specifies a regular expression, a case-sensitive string of 1 to 256 characters.
Description
Use display loopback-detection to display the operating status of the loopback detection function.
Example
# Display the loopback detection operating status.
<Sysname> display loopback-detection
Loopback-detection is running.
Detection interval is 30 second(s).
Action mode: None
Loopback-detection is enabled on the following VLAN(s):
1, 20, 315, 1001, 2008, 2010-2015, 2026
Loopback is detected on the following interface(s):
GigabitEthernet4/0/2
Table 1 Command output
|
Field |
Description |
|
Detection interval is 30 second(s) |
The loopback detection interval is 30 seconds. |
|
Action mode |
Loopback detection action: · None—When detecting a looped port, the system prints log information and sends trap messages. · Shutdown—When detecting a looped port, the system prints log information, sends trap messages, and shuts down the port. After the port status detection timer (set by the shutdown-interval command) expires, the system will bring up the port. For more information about the port status detection timer, see Fundamentals Configuration Guide. |
loopback-detection action
Syntax
loopback-detection action { none | shutdown }
undo loopback-detection action
View
System view
Default level
2: System level
Parameters
none: Sets the loopback detection action to none. If you specify this keyword, the system only prints log information and sends trap messages when it detects a looped port.
shutdown: Sets the loopback detection action to shutdown. If you specify this keyword, the system prints log information, sends trap messages, and shuts down the port to disable the port from sending and receiving packets (including loopback detection frames) when it detects a looped port. After the port status detection timer (set by the shutdown-interval command) expires, the system will bring up the port.
Description
Use loopback-detection action to configure the loopback detection action.
Use undo loopback-detection action to restore the default.
By default, the loopback detection action is none.
Related commands: display loopback-detection.
Example
# Set the loopback detection action to shutdown.
<Sysname> system-view
[Sysname] loopback-detection action shutdown
loopback-detection enable
Syntax
In system view:
loopback-detection enable vlan { vlan-list | all }
undo loopback-detection enable vlan { vlan-list | all }
In VLAN view:
loopback-detection enable
undo loopback-detection enable
View
System view, VLAN view
Default level
2: System level
Parameters
vlan-list: Specifies a list of existing VLANs, in the format of vlan-list = { vlan-id [ to vlan-id ] }&<1-10>, where vlan-id represents the VLAN ID in the range of 1 to 4094, and &<1-10> indicates you can specify up to 10 vlan-id [ to vlan-id ] parameters.
all: Specifies all existing VLANs.
Description
Use loopback-detection enable to enable loopback detection.
Use undo loopback-detection enable to disable loopback detection.
By default, the loopback detection function is disabled.
In system view, you can enable loopback detection for ports in multiple or all existing VLANs.
In VLAN view, you can enable loopback detection only for ports in the VLAN.
Related commands: display loopback-detection.
Example
# Enable loopback detection for VLAN 10 through VLAN 100 in system view.
<Sysname> system-view
[Sysname] loopback-detection enable vlan 10 to 100
# Enable loopback detection for VLAN 10 in VLAN view.
<Sysname> system-view
[Sysname] vlan 10
[Sysname-vlan10] loopback-detection enable
loopback-detection interval-time
Syntax
loopback-detection interval-time interval
undo loopback-detection interval-time
View
System view
Default level
2: System level
Parameters
interval: Specifies the loopback detection interval (in seconds) in the range of 1 to 300.
Description
Use loopback-detection interval-time to configure the loopback detection interval.
Use undo loopback-detection interval-time to restore the default.
By default, the loopback detection interval is 30 seconds.
Related commands: display loopback-detection.
Example
# Set the loopback detection interval to 10 seconds.
<Sysname> system-view
[Sysname] loopback-detection interval-time 10
