carrier

Function

The carrier command configures the delay in reporting an interface status change event.

The undo carrier command restores the default delay in reporting an interface status change event.

By default, the delay in reporting an interface Up event is 2000 milliseconds, and the delay in reporting an interface Down event is 0 milliseconds.

Format

carrier { up-hold-time | down-hold-time } interval

undo carrier { up-hold-time | down-hold-time }

Parameters

Parameter	Description	Value
up-hold-time interval	Specifies the delay in reporting an interface Up event.	The value is 0 or an integer that ranges from 50 to 120000, in milliseconds.
down-hold-time interval	Specifies the delay in reporting an interface Down event.	The value is 0 or an integer that ranges from 1000 to 120000, in milliseconds.

Views

Ethernet interface view, GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, port group view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

The physical status of an Ethernet interface can be Up or Down. When the physical status changes, the system notifies upper-layer protocol modules (such as the routing and forwarding modules) of the change to direct packet receiving and forwarding. The system also automatically generates traps and logs to remind users to perform corresponding operations on physical links. For example, when the physical status of the active interface in an interface protection group changes from Up to Down, the system immediately instructs the upper-layer service forwarding protocol to send service packets from the standby interface.

If frequent physical status changes are reported to the system, extra system costs are generated. You can configure the delay in reporting physical status changes to solve the problem. The system is unaware of the physical status changes on interfaces within the configured delay. If the interface physical status is not recovered after the delay expires, the physical status changes are reported to the system.

You can configure the delay in reporting physical status changes based on the network connection status.

Setting a long delay

For example, an interface frequently alternates between Up and Down states at an interval shorter than the IP route convergence time. In this case, the upper-layer protocol does not need to sense the physical status changes. You can set a long delay in reporting physical status changes to avoid unnecessary routing entry refreshing caused by frequent physical status changes.
Setting a short delay

For example, when the physical status of the active interface in an interface protection group changes from Up to Down, the system needs to immediately instruct the upper-layer service forwarding protocol to send service packets from the standby interface. In this case, you can set a short delay in reporting physical status changes to ensure real-time service switchover.

Precautions

If you run the carrier command multiple times in the same interface view, only the latest configuration takes effect.

Example

# Set the delay in reporting an interface Up event to 1000 milliseconds on GE0/0/1.

<HUAWEI> system-view
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] carrier up-hold-time 1000