No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


Configuration Guide - Interface Management

S1720, S2700, S5700, and S6720 V200R010C00

This document describes the principles and configurations of interfaces and provides configuration examples.

Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Configuring Internal Loopback Detection

Configuring Internal Loopback Detection


When testing some special functions, for example, locating an Ethernet fault, you need to enable loopback detection on Ethernet interfaces to check whether the interfaces are working properly. After loopback detection is enabled on an Ethernet interface, the interface is in Up state if it works properly, and is in Down state if it fails.

In internal loopback detection, a packet from an interface is sent back to the interface through the internal chip. Internal loopback detection checks whether the connection between the interface and internal chip is normal. In external loopback detection, a packet from an interface is sent back to the interface through a loopback connector. External loopback detection checks whether the interface properly sends and receives packets. Currently, the device supports only internal loopback detection. As shown in Figure 3-11, after internal loopback detection is enabled on GE0/0/1, the chip generates some test packets, and these test packets are sent back to the chip through GE0/0/1. The internal loopback detection is complete.
Figure 3-11  Internal loopback detection

After internal loopback detection is enabled on an interface, other functions may be affected. After the test is complete, run the undo loopback command to disable loopback detection. The original configuration on the interface is then restored.


  1. Run:


    The system view is displayed.

  2. Run:

    interface interface-type interface-number

    The interface view is displayed.

  3. Run:

    loopback internal

    Internal loopback detection is configured on the Ethernet interface.

    By default, internal loopback detection is disabled on an Ethernet interface.

Checking the Configuration

Run the display interface [ interface-type [ interface-number ] ] command in any view or the display this interface command in the interface view to check the current interface status. Check the Loopback field in the command output.


After loopback detection is enabled on an interface, the Speed field in the display this interface command output indicates the configured interface rate or the rate of the installed optical module, copper module, or network cable, and the Bandwidth field in the display interface ethernet brief command output indicates the actual interface rate.

Updated: 2019-12-28

Document ID: EDOC1000141936

Views: 50378

Downloads: 783

Average rating:
This Document Applies to these Products

Related Version

Related Documents

Previous Next