loopback

Function

The loopback command enables loopback on an Ethernet interface.

The undo loopback command disables loopback.

By default, loopback is disabled on Ethernet interfaces.

Format

loopback { local | remote }

undo loopback

Parameters

Parameter	Description	Value
local	Specifies local loopback. Local loopback means that a packet from an interface is sent back to this interface inside the system.	-
remote	Specifies remote loopback. Remote loopback means that the local interface sends a packet from the peer interface (remote end) back to the peer interface rather than forward the packet to the destination address.	-

Parameter

Description

Value

local

Specifies local loopback.

Local loopback means that a packet from an interface is sent back to this interface inside the system.

remote

Specifies remote loopback.

Remote loopback means that the local interface sends a packet from the peer interface (remote end) back to the peer interface rather than forward the packet to the destination address.

Views

Layer 2 100GE interface view, 100GE interface view, Layer 2 10GE interface view, 10GE interface view, 25GE-L2 view, 25GE interface view, 400GE-L2 view, 400GE interface view, Layer 2 40GE interface view, 40GE interface view, Layer 2 50GE interface view, 50GE interface view, FlexE-100G interface view, FlexE-400G interface view, FlexE-50G interface view, FlexE-50|100G interface view, FlexE interface view, Layer 2 GE interface view, GE optical interface view, GE interface view, GE electrical interface view

Default Level

3: Management level

Task Name and Operations

Task Name	Operations
device-mgr	write

Usage Guidelines

Usage Scenario

If you want to locate a system fault, run the loopback local command to enable local loopback.
If you want to locate a link fault or test the quality of a link, run the loopback remote command to enable remote loopback on a interface.

Configuration Impact

In normal situations, interfaces are not allowed to work in loopback mode; otherwise, traffic is looped, causing service interruption.

Example

# Enable local loopback on GE 0/1/0.

<HUAWEI> system-view
[~HUAWEI] interface GigabitEthernet 0/1/0
[~HUAWEI-GigabitEthernet0/1/0] loopback local