How to check if interconnected electrical interfaces cannot go up?
1. Checking the Configuration of Electrical Interfaces on Both Ends
- Check whether electrical interfaces on both ends are configured correctly.
Ensure that the interfaces are not manually shut down or shut down due to certain errors. In addition, ensure that there is no configuration that prevents the interfaces from going up, for example, loop detection.
<HUAWEI> display interface GigabitEthernet 0/0/1 GigabitEthernet0/0/1 current state : ERROR DOWN Line protocol current state : DOWN¡¡
| Table 1 Error-down type list | ||
| Error-Down List | Scenario | Recovery Method |
| auto-defend | After the auto-defend action command is used to configure actions against attack sources, the interface that receives attack packets is shut down to prevent the device from attacks. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| bpdu-protection | On an STP-enabled network where BPDU protection is configured on an edge port, if malicious attackers send bogus BPDUs to attack the switching device, the switching device sets the edge port to Down immediately after the edge port receives BPDUs. As a result, all services on the edge port are interrupted. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| efm-remote-failure | The efm trigger error-down command associates an error event with an interface. When EFM detects critical-event, dying-gasp, link-fault, or timeout faults, the protocol status of the interface becomes Down and all services on the interface are interrupted. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| efm-threshold-event | When link monitoring is configured for an interface on a link, the link is considered unavailable, if the number of errored frames, errored codes, or errored frame seconds detected by the interface reaches or exceeds the threshold within a period. You can associate an EFM crossing event with an interface. Then the system sets the administrative status of the interface to Down. In this manner, all services on the interface are interrupted. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| error-statistics | When an Ethernet interface configured with a backup link receives error packets, faults such as packet loss occur. To ensure nonstop service transmission, when the number of received error packets reaches the alarm threshold, the interface is shut down and services are switched to the backup link. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| link-flap | Network cable faults or active/standby switchovers may cause an interface to alternate between Up and Down. You can configure link flapping protection. When the device receives an interface Up/Down message, it checks the interface flapping count and link flapping detection interval. If the interface flapping count reaches the limit within the specified period, the device shuts down interface. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| port-security | After port security is enabled on an interface, MAC addresses learned by the interface change to secure dynamic MAC addresses. If the port-security protect-action command sets the security protection action to shutdown, the interface is shut down when the number of learned MAC addresses on the interface exceeds the upper limit or static MAC address flapping is detected. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
| mac-address-flapping | If the user network where the device is deployed does not support loop prevention protocols, configure a loop prevention action for the device to perform when the device detects MAC address flapping. The device shuts down an interface when detecting MAC address flapping on the interface. | If the recovery time is configured, the interface is recovered when the time is reached. If no recovery time is configured, run the undo shutdown command in the interface view to recover the interface. |
Check the current state value in the command output.
Administratively down: indicates that the interface is manually shut down. In this case, run the undo shutdown command on the interface.
ERROR DOWN: indicates that the interface is shut down due to an error. In this case, check whether BPDU protection or auto-defend is configured.
DOWN: Proceed to the next step.
<HUAWEI> display loopback-detect Loopback-detect sending-packet interval: 5 ------------------------------------------------------------- Interface RecoverTime Action Status ------------------------------------------------------------- GigabitEthernet0/0/1 30 block NORMAL ------------------------------------------------------------- <HUAWEI> display loop-detection interface gigabitethernet 0/0/1 The port is enabled. The port's status list: Status WorkMode Recovery-time EnabledVLAN Shutdown 30 100
The command output shows that the Status value is Normal, and the WorkMode value is Shutdown, indicating that loop detection is enabled on this interface. The interface is shut down because a loop is detected.
- Check the work mode of the combo interface.
Before using the combo interface, ensure that the optical interface is not used, and the Combo port is not forcibly configured as an optical interface.
<HUAWEI> display interface gigabitethernet 0/0/1 GigabitEthernet0/0/1 current state : DOWN Line protocol current state : DOWN Description:HUAWEI, Quidway Series, GigabitEthernet0/0/1 Interface ¡¡Port Mode: COMBO AUTO Current Work Mode: COPPER Speed : 100, Loopback: NONE ¡¡
Port Mode values:
COMBO AUTO: The combo interface automatically selects the working mode.
FORCE FIBER: The combo interface is configured to work as an optical interface.
FORCE COPPER: The combo interface is configured to work as an electrical interface.
If the value is FORCE FIBER, run the combo-port auto command on the interface so it can automatically choose the working mode based on the physical transmission media.
NOTE:
Identify a combo interface based on the interface ID on the switch panel. If two interfaces have the same ID but connect to different transmission media, the two interfaces are multiplexed as a combo port. A combo interface can work as an electrical or optical interface.
- Ensure that the two interfaces have the same duplex mode, rate, and negotiation mode.
The two interfaces must both work in non-auto-negotiation mode or auto-negotiation mode. If they both work in non-auto-negotiation mode, they have the same rate and duplex mode.
<HUAWEI> display interface GigabitEthernet 0/0/1 GigabitEthernet0/0/1 current state : DOWN Line protocol current state : DOWN Description:HUAWEI, Quidway Series, GigabitEthernet0/0/1 Interface ¡¡ Port Mode: COMMON COPPERSpeed : 1000, Loopback: NONEDuplex: FULL, Negotiation: DISABLE
If the Negotiation value is ENABLE, an interface works in auto-negotiation mode. The value DISABLE indicates that an interface works in non-auto-negotiation mode.
Configure the interface to work in auto-negotiation mode: <HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] negotiation auto Configure the interface to work in non-auto-negotiation mode: <HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] undo negotiation auto [HUAWEI-GigabitEthernet0/0/1] speed 100 [HUAWEI-GigabitEthernet0/0/1] duplex full //When the interface works in non-auto-negotiation mode, the interface works in full duplex mode by default, so the duplex command does not need to be configured. This command is not supported on some cards.
- Configure the interface rate.
If both interfaces are configured to work in auto-negotiation mode but they cannot go Up, configure both interfaces to work in non-auto-negotiation mode and at a rate of 100 M/bits or 10 M/bits.
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] undo negotiation auto [HUAWEI-GigabitEthernet0/0/1] speed 100
If one interface is a GE electrical interface while the other interface is a 100M or 10M electrical interface, configure them to work in auto-negotiation mode and configure the GE electrical interface to work at 100 M/bits or 10 M/bits.
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-igabitEthernet0/0/1] auto speed 100
- Check whether the rate decrease auto-negotiation function needs to be configured.
If the two interfaces work in auto-negotiation mode and the negotiated interface rate depends on the transmission rate of the network cable, run the set ethernet speed down-grade command to configure rate decrease auto-negotiation. Assume that the network cable can only work at 100 Mbit/s or 10 Mbit/s. The two GE interfaces can decrease the negotiated rate to 100 Mbit/s or 10 Mbit/s and go Up, even if they can work at a maximum rate of 1000 Mbit/s. This command is supported only in V200R005 and later versions.
<HUAWEI> system-view [HUAWEI] set ethernet speed down-grade
2. Checking the Network Cable
- Check whether the network cable is correctly connected.
Ensure that a same network cable is used to connect the two interfaces. If the two interfaces are connected through the optical distribution frame, ensure that the network cables are connected correctly. Ensure that the interfaces are connected correctly, and ensure that the cable is firmly installed and intact.
- Ensure that the cable length complies with related standards.
According to Ethernet cable standards, the network cable length cannot exceed 100 meters.
- Ensure that the network cable specifications are correct.
A GE electrical interface working at 1000 M/bits cannot go Up when it uses a network cable of a category lower than Category 5. A network cable of a category higher than Category 5 is recommended for the connection between electrical interfaces.
- Check the status of line pairs in a cable.
If an of the four line pairs in a cable is damaged, electrical interfaces cannot go Up. Use a cable tester or the virtual cable test function of the electrical interface on a switch to check the network cable quality. When using the virtual-cable-test command, the interface will alternate between Up and Down once. For other precautions related to the command, see the Command Reference guide.
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] virtual-cable-test Warning: The command will stop service for a while, Continue?[Y/N]y Info: This operation may take a few seconds. Please wait for a moment..........done. Pair A length: 1meter(s) Pair B length: 1meter(s) Pair C length: 1meter(s) Pair D length: 1meter(s)Pair A state: OkPair B state: OkPair C state: OkPair D state: Ok
If the Pair state value is OK in the command output, the line pairs are intact. If any other state is displayed, change a network cable and test again.
- Check whether any metal reeds in an interface have sunk or shifted.
3. Checking Whether the Deployment Environment Complies with Standards
- Check whether the switch is grounded.
- Check whether the network cable is routed in parallel with high-current cables.
4.Conducting Related Tests
- Conduct a loopback test.
Configure the loopback test function on an interface. If the interface cannot go Up, hardware faults occur. Avoid loops when conducting the loopback test.
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] loopback internal [HUAWEI-GigabitEthernet0/0/1] display this interface GigabitEthernet0/0/1 current state : UP Line protocol current state : UP
NOTE:
During a loopback test, Ethernet interfaces or links cannot work properly. After the test is complete, run the undo loopback command on the interface to cancel the loopback test function.
- Connect the two interfaces to a PC, and check whether they can go Up.
Connect the two interfaces to a PC in turn, and check whether the interfaces can go Up and check the rate when they are Up. The fault may occur on the interface that cannot go Up when connected to the PC.
- Replace the devices one by one until you locate the fault.
This test is to locate whether the fault occurs on the local interface, network cable link, or remote interface. First replace a network cable, and use it to directly connect the two interfaces. Then replace the interfaces and switches one by one, and locate the failure point.
5.Collecting Information and Seeking Technical Support
If the fault persists, collect related information and seek technical support.
- Collecting Fault Information
Collect operation results of the preceding steps and record the results in a file.
Collect all diagnostic information and export the information to a file.
Run the display diagnostic-information file-name command in the user view to collect diagnostic information and save the information to a file.
<HUAWEI> display diagnostic-information dia-info.txt Now saving the diagnostic information to the device 100% Info: The diagnostic information was saved to the device successfully.
When the diagnostic file is generated, you can export the file from the device using FTP, SFTP, or SCP.
NOTICE:
You can run the dir command in the user view to check whether the file is generated.
You can also run the display diagnostic-information command and save terminal logs in a diagnostic file on a disk.
If this command displays a long output, press Ctrl+C to abort this command.
This command displays diagnostic information, which helps locate faults but may affect system performance. For example, CPU usage may become high. Therefore, do not use this command when the system is running properly.
Running the display diagnostic-information command simultaneously on multiple terminals connected to the device is prohibited. This is because CPU usage of the device may obviously increase and the device performance may be degraded.
Collect the log and trap information on the device and export the information to files.
Run the save logfile all command in the user view to save the logs in the user log buffer area and diagnostic log buffer area to the user log file and diagnostic log file, respectively.
<HUAWEI> save logfile all Info: Save logfile successfully. Info: Save diagnostic logfile successfully.
When the diagnostic file is generated, you can export the file from the device using FTP, SFTP, or SCP.
NOTE:
You can also run the display logbuffer and display trapbuffer commands to view the log and trap information on the device, and save the information in diagnostic files on a disk.
- Seek technical support.
[email protected].
NOTE:
Technical support personnel will provide instructions for you to submit all the collected information and files, so that they can locate faults.
