How Do I Configure Single-Interface Loop Detection

Latest reply: Mar 4, 2016 22:27:39 1121 1 0 0
How Do I Configure Single-Interface Loop Detection?
  • x
  • convention:

Created Mar 4, 2016 22:27:39 Helpful(0) Helpful(0)

Switches can detect only external loops that occur on a single interface. After external loop detection is enabled, the switch sends packets periodically to check whether an external loop occurs on an interface. When a loop is found on an interface, the switch performs the specified action on the interface. In versions earlier than V200R002, the switch sets the interface state to blocking by default. In V200R002 and later versions, the switch sets the interface state to shutdown by default.

Usage Scenario
Generally, single-interface loop detection is used on downlink interfaces of newly deployed switches to help field engineers discover incorrect cable connections.

It is recommended that you set the action for interfaces with loops to block.

Configuration Procedure
After you enable loop detection globally, this function is enabled on all interfaces.

[Quidway] loopback-detect enableModular switches of V200R001 and later versions support loop detection in eight VLANs on an interface.

Fixed switches of V100R005 and later versions support loop detection in eight VLANs on an interface. In addition to trap, shutdown, and block, the action for interfaces with loops can be set to nolearn (stop learning MAC addresses).

The following configuration is performed on fixed switches:

[Quidway-Ethernet0/0/1] loopback-detect packet vlan 20 21 22 23 24 25 26 27
[Quidway-Ethernet0/0/1] loopback-detect action nolearn

Modular switches of V200R001 and later versions and fixed switches of V100R005 and later versions can generate loop traps, and the traps contain VLANs where loops have occurred.

The following is an example of loop trap:

#Jan 1 2008 06:43:54-08:00 Quidway LDT/4/Porttrap:OID1.3.6.1.4.1.2011.5.25.174.3.3 Loopback does exist on interface(5) Ethernet0/0/1 ( VLAN 20 ) , loopback detect status: 4.(1:normal; 2:block;3:shutdown; 4:trap; 5:nolearn)

Precautions
Loop detection is an auxiliary tool and consumes system resources. When loop detection is complete, run the undo loopback-detect enable command to disable this function.

  • x
  • convention:

Reply

Reply
You need to log in to reply to the post Login | Register

Notice: To protect the legitimate rights and interests of you, the community, and third parties, do not release content that may bring legal risks to all parties, including but are not limited to the following:
  • Politically sensitive content
  • Content concerning pornography, gambling, and drug abuse
  • Content that may disclose or infringe upon others ' commercial secrets, intellectual properties, including trade marks, copyrights, and patents, and personal privacy
Do not share your account and password with others. All operations performed using your account will be regarded as your own actions and all consequences arising therefrom will be borne by you. For details, see " Privacy."
If the attachment button is not available, update the Adobe Flash Player to the latest version!

Login and enjoy all the member benefits

Login
Fast reply Scroll to top