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| Title | Size | Download |
|---|---|---|
| 08-Loop detection commands | 67.00 KB |
Contents
loopback-detection global action
loopback-detection global enable
loopback-detection interval-time
Loop detection commands
display loopback-detection
Use display loopback-detection to display the loop detection configuration and status.
Syntax
display loopback-detection
Views
Any view
Predefined user roles
network-admin
network-operator
context-admin
context-operator
Example
# Display the loop detection configuration and status.
<Sysname> display loopback-detection
Loopback detection is enabled.
Loopback detection interval is 30 second(s).
Loopback is detected on following interfaces:
Interface Action mode VLANs
GigabitEthernet1/2/5/3 None 10
Table 1 Command output
|
Field |
Description |
|
Action mode |
Loop protection action: · Block—When a loop is detected on a port, the device performs the following operations: ¡ Logs the event. ¡ Disables the port from learning MAC addresses. ¡ Blocks the port. · None—When a loop is detected on a port, the device logs the event without taking any action on the port. · No-learning—When a loop is detected on a port, the device logs the event and disables the port from learning MAC addresses. · Shutdown—When a loop is detected on a port, the device performs the following operations: ¡ Logs the event. ¡ Shuts down the port to disable it from receiving or sending frames. The device automatically sets the port to the forwarding state after a time interval. Set the time interval by using the shutdown-interval command (see Fundamentals Command Reference). |
|
VLANs |
VLANs where loops were detected. |
loopback-detection action
Use loopback-detection action to set the loop protection action on a per-port basis.
Use undo loopback-detection action to restore the default.
Syntax
In Layer 2 Ethernet interface view:
loopback-detection action { block | no-learning | shutdown }
undo loopback-detection action
In Layer 2 aggregate interface view:
loopback-detection action shutdown
undo loopback-detection action
Default
When the device detects a loop on a port, it logs the event without taking any action on the port.
Views
Layer 2 Ethernet interface view
Layer 2 aggregate interface view
Predefined user roles
network-admin
context-admin
Parameters
block: Enables the block mode. If a loop is detected, the device performs the following operations:
· Logs the event.
· Disables MAC address learning.
· Blocks the port.
Layer 2 aggregate interfaces do not support this keyword.
no-learning: Enables the no-learning mode. If a loop is detected, the device logs the event and disables MAC address learning on the port. Layer 2 aggregate interfaces do not support this keyword.
shutdown: Enables the shutdown mode. If a loop is detected, the device logs the event and shuts down the port. The device automatically sets the port to the forwarding state after the time interval set by using the shutdown-interval command (see Fundamentals Command Reference).
Usage guidelines
To set the loop protection action globally, use the loopback-detection global action command.
The global action applies to all ports. The per-port action applies to the individual ports. The per-port action takes precedence over the global action.
Example
# Set the loop protection action to shutdown on GigabitEthernet 1/2/5/1.
<Sysname> system-view
[Sysname] interface gigabitethernet 1/2/5/1
[System-GigabitEthernet1/2/5/1] loopback-detection action shutdown
display loopback-detection
loopback-detection global action
loopback-detection enable
Use loopback-detection enable to enable loop detection on a per-port basis.
Use undo loopback-detection enable to disable loop detection on a port.
Syntax
loopback-detection enable vlan { vlan-id-list | all }
undo loopback-detection enable vlan { vlan-id-list | all }
Default
Loop detection is disabled on ports.
Views
Layer 2 Ethernet interface view
Layer 2 aggregate interface view
Predefined user roles
network-admin
context-admin
Parameters
vlan-id-list: Specifies a space-separated list of up to 10 VLAN items. Each item specifies a VLAN ID or a range of VLAN IDs in the form of vlan-id1 to vlan-id2. The value range for VLAN IDs is 1 to 4094. The ID for vlan-id2 must be equal to or greater than the ID for vlan-id1.
all: Specifies all existing VLANs.
Usage guidelines
You can enable loop detection globally or on a per-port basis. When a port receives a detection frame in any VLAN, the loop protection action is triggered on that port, regardless of whether loop detection is enabled on it.
Example
# Enable loop detection on GigabitEthernet 1/2/5/1 for VLAN 10 through VLAN 20.
<Sysname> system-view
[Sysname] interface gigabitethernet 1/2/5/1
[System-GigabitEthernet1/2/5/1] loopback-detection enable vlan 10 to 20
display loopback-detection
loopback-detection global enable
loopback-detection global action
Use loopback-detection global action to set the global loop protection action.
Use undo loopback-detection global action to restore the default.
Syntax
loopback-detection global action shutdown
undo loopback-detection global action
Default
When the device detects a loop on a port, it logs the event without taking any action on the port.
Views
System view
Predefined user roles
network-admin
context-admin
Parameters
shutdown: Enables the shutdown mode. If a loop is detected, the device logs the event and shuts down the port. The device automatically sets the port to the forwarding state after you set the time interval by using the shutdown-interval command (see Fundamentals Command Reference).
Usage guidelines
To set the loop protection action on a per-port basis, use the loopback-detection action command in interface view.
The global action applies to all ports. The per-port action applies to the individual ports. The per-port action takes precedence over the global action.
Example
# Set the global loop protection action to shutdown.
<Sysname> system-view
[System] loopback-detection global action shutdown
Related commands
display loopback-detection
loopback-detection action
loopback-detection global enable
Use loopback-detection global enable to enable loop detection globally.
Use undo loopback-detection global enable to disable loop detection globally.
Syntax
loopback-detection global enable vlan { vlan-id-list | all }
undo loopback-detection global enable vlan { vlan-id-list | all }
Default
Loop detection is globally disabled.
Views
System view
Predefined user roles
network-admin
context-admin
Parameters
vlan-id-list: Specifies a space-separated list of up to 10 VLAN items. Each item specifies a VLAN ID or a range of VLAN IDs in the form of vlan-id1 to vlan-id2. The value range for VLAN IDs is 1 to 4094. The ID for vlan-id2 must be equal to or greater than the ID for vlan-id1.
all: Specifies all existing VLANs.
Usage guidelines
You can enable loop detection globally or on a per-port basis. When a port receives a detection frame in any VLAN, the loop protection action is triggered on that port, regardless of whether loop detection is enabled on it.
Example
# Globally enable loop detection for VLAN 10 through VLAN 20.
<Sysname> system-view
[System] loopback-detection global enable vlan 10 to 20
Related commands
display loopback-detection
loopback-detection enable
loopback-detection interval-time
Use loopback-detection interval-time to set the loop detection interval.
Use undo loopback-detection interval-time to restore the default.
Syntax
loopback-detection interval-time interval
undo loopback-detection interval-time
Default
The loop detection interval is 30 seconds.
Views
System view
Predefined user roles
network-admin
context-admin
Parameters
interval: Sets the loop detection interval in the range of 1 to 300 seconds.
Usage guidelines
With loop detection enabled, the device sends loop detection frames at the specified interval. A shorter interval offers more sensitive detection but consumes more resources. Consider the system performance and loop detection speed when you set the loop detection interval.
Example
# Set the loop detection interval to 10 seconds.
<Sysname> system-view
[Sysname] loopback-detection interval-time 10
Related commands
display loopback-detection
