Got it

[All About Switches] Q&A: What Can I Do If An Ethernet Interface Frequently Alternates Between Up and Down States? Highlighted

Latest reply: Jun 24, 2018 13:26:02 833 1 1 0 0

Hi, everyone! Today I’m going to introduce what can i do if an ethernet interface frequently alternates between up and down states?

A:An Ethernet interface frequently alternates betweenUp and Down states. The possible causes are as follows:

a. The cable is not properly connected to the interface.

b. The twisted pair or fiber connected to the interface istoo long or the fiber attenuation is high.

c. The local and remote interfaces work at different duplexmodes , speeds, negotiation modes.

d. The local and remote interfaces, interface modules, ordevices are faulty.


Step 1     
Check whether the cable and interface modules areproperly installed on the localand remote devices. If the fault persists after the cable and interface modulesare properly installed, go to step 2.

Step 2      Check whether the two interfaces have the same duplex mode, rate, andnegotiation mode. Run thedisplay interfacecommand on the two interfaces to check the rates,duplex modes, and negotiation modes of the interfaces.

If the fault persists, go to step 3.

Step3      Check whether theinterface modules and the link between the interfaces work properly. If the twointerfaces are connected by a twisted pair, check the following items.

If the two interfaces are connected by fibers,check the following items.

If the fault persists, go to step4.

Step4      Check whether thelocal or remote device has a hardware fault.

Connect the twisted pair or fibers to anotherinterface. If the remote device is a powered device (PD), check whether thepower of the remote device exceeds the maximum power of the interface.

If the fault persists, go to step 5.

Step 5     Check the interface Up/Down log to rectify thefault.


For details, see the S Series Switches InterfaceTroubleshooting.     
Step 1: Log in to the enterprise technical supportwebsite at
Step 2: Click Switches.

Step 3: Click the name of the product to bequeried, for example, S7700.

Step 4: Choose Documentation> S7700 Troubleshooting – Preliminary to find theTroubleshootingfor your switch model.

Step 5: Open the Troubleshooting.Choose Interface Faults > An Ethernet Interface FrequentlyAlternates Between Up and Down States in the navigation tree on the left,and follow the instructions.

S7700&S9700 Series Switches Troubleshooting -Preliminary|21782164|21782186|22318632|6805481

This is what I want to talk about/share with you today, thank you!

This article contains more resources

You need to log in to download or view. No account? Register

  • x
  • convention:

MVE Created Jun 24, 2018 13:26:02

good job done
View more
  • x
  • convention:


You need to log in to comment 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 " User Agreement."

My Followers

Login and enjoy all the member benefits


Are you sure to block this user?
Users on your blacklist cannot comment on your post,cannot mention you, cannot send you private messages.
Please bind your phone number to obtain invitation bonus.