Troubleshooting Method for an Ethernet Interface that Frequently Alternates Between Up and Down States Highlighted

Created Jul 19, 2017 17:03:31Latest reply Aug 09, 2017 15:41:32 863 2 0 1

 An Ethernet Interface Frequently Alternates Between Up and Down States

1.         Check whether the interface modules and the link between the local and remote interfaces work properly.

Check Item

Expected Result

Follow-up Procedure

Twisted pair working status

The tester shows that the twisted pair works properly.

If the twisted pair is faulty, replace it.

Twisted pair length

The twisted pair length does not exceed 100 m.

Note:

The 10M/100M/1000M electrical interfaces use RJ45 connectors and Category 5 or higher twisted pairs. The maximum transmission distance of such cables is 100 m.

If the twisted pair length exceeds 100 m, perform either of the following operations:

1.    Shorten the distance between the two devices.

2.    If the distance between the two devices cannot be shortened, deploy a repeater, hub, or switch between them.

Optical fiber working status

The tester shows that optical signals are sent and received properly.

In a loopback test, the two interfaces are Up.

If optical signals cannot be sent or received, replace the optical fibers. If the fault persists, replace the optical modules.

Types of optical modules and fibers

The optical fiber type matches the optical module type. For details about mappings between optical module types and optical fiber types, see "Pluggable Modules for Interfaces" in the appropriate hardware description.

If the optical fiber type does not match the optical module type, replace the optical modules or fibers.

Optical fiber length and maximum transmission distance of optical modules

The optical fiber length is shorter than the maximum transmission distance of the optical modules. For the maximum transmission distance supported by different optical modules, see "Pluggable Modules for Interfaces" in the appropriate hardware description.

If the optical fiber length exceeds the maximum transmission distance of the optical modules, shorten the distance between the devices or use optical modules with a longer transmission distance.

Optical signal attenuation

The tester shows that the optical signal attenuation is within the allowed range. For the attenuation range, see "Pluggable Modules for Interfaces" in the appropriate hardware description.

If the attenuation is high, replace the optical fibers. If the fault persists, shorten the distance between the devices and use shorter optical fibers.

 

If the fault persists, go to step 2.

2.         Check whether the two interfaces have the same duplex mode, rate, and negotiation mode.

Run the display interface command on the two interfaces to check their duplex modes, rates, and negotiation modes.

Check Item

Description

Follow-up Procedure

Negotiation

Auto-negotiation mode of the interface:

1.    ENABLE: indicates that the interface works in auto-negotiation mode.

2.    DISABLE: indicates that the interface works in non-auto-negotiation mode.

The two interfaces must work in the same negotiation mode.

Run the negotiation auto command in the interface view to configure the interfaces to work in auto-negotiation mode. If the fault persists, configure the interfaces to work in non-auto-negotiation mode and use the same rate and duplex mode.

Speed

Current rate of the interface.

If the rates of the interfaces are different in non-auto-negotiation mode, run the speed command in the interface view to configure the interfaces to work at the same rate.

Duplex

Duplex mode of the interface.

If the duplex modes of the interfaces are different in non-auto-negotiation mode, run the duplex command in the interface view to configure the interfaces to work in the same duplex mode.

 

If the fault persists, go to step 3.

3.         Check the interface Up/Down log to rectify the fault.

Up/Down Log Information

Possible Cause

Follow-up Procedure

Multiple Up/Down logs are generated on the interface within a short period (60s). The interface may alternate between Up and Down states intermittently.

Because the remote device is restarting, the local interface alternates between Up and Down states intermittently for multiple times.

No action is required. Wait until the remote device finishes restarting.

A group of interfaces alternate between Up and Down states simultaneously.

An active/standby switchover is performed on the remote device. When multiple interfaces of the local device connect to the same remote device, the interfaces alternate between Up and Down states simultaneously if an active/standby switchover occurs on the remote device.

No action is required. Wait until the remote device finishes the active/standby switchover.

It takes a long time for the interface to change from Down to Up.

This log is informational. The remote device performs operations on the local interface.

No action is required.

The Up/Down logs are generated on the interface at different times. In this period, the interface alternates between Up and Down states intermittently at an interval shorter than 1s.

1.    The optical module does not match the hardware, the optical module is sensitive to the signal jitter, or the receive optical power is too low.

2.    The remote or local interface is faulty.

3.    Port protection is configured on the remote device.

1.    Replace the optical module and check whether the optical module and fiber are properly connected.

2.    Connect the local interface to another remote interface.

3.    Disable port protection on the remote device.

 

If the fault persists, go to step 4.

4.         Check whether the local or remote device has a hardware fault.

Connect the twisted pair or optical fibers to another interface.

If the fault persists, go to step 5.

5.         Collect the following information and contact technical support personnel.

A. Results of the preceding troubleshooting procedure.

B. Configuration file, logs, and alarms of the device.

 

This post was last edited by yWX335364 at 2017-7-19 17:06.
  • x
  • convention:

gululu  Admin   Created Jul 19, 2017 17:46:03 Helpful(0) Helpful(0)

thanks
  • x
  • convention:

Come on!
m7g     Created Aug 09, 2017 15:41:32 Helpful(0) Helpful(0)

Good, thanks
  • x
  • convention:

WBR, Evgeny K.
-----------------
Mark my post "BEST ANSWER" if my post / answer

Responses

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

Notice:To ensure 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 not limited to politically sensitive content, content concerning pornography, gambling, drug abuse and trafficking, content that may disclose or infringe upon others' intellectual properties, including commercial secrets, 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 Policy.”
If the attachment button is not available, update the Adobe Flash Player to the latest version!
Fast reply Scroll to top