Troubleshooting hardware

Interface issues

CRC error

Symptom

You can see CRC error packets on the interface with the display interface command.

<Sysname> display interface ten-gigabitethernet 2/0/0

Ten-GigabitEthernet2/0/0

Current state: DOWN

Line protocol state: DOWN

Description: Ten-GigabitEthernet2/0/0 Interface

Bandwidth: 1000000 kbps

Maximum transmission unit: 1500

Internet address: 2.1.1.2/24 (primary)

IP packet frame type: Ethernet II, hardware address: 0000-fc00-9276

IPv6 packet frame type: Ethernet II, hardware address: 0000-fc00-9276

Loopback is not set

Media type is twisted pair, port hardware type is 1000_BASE_T

Port priority: 0

1000Mbps-speed mode, full-duplex mode

Link speed type is autonegotiation, link duplex type is autonegotiation

Flow-control is not enabled

Maximum frame length: 9216

Last clearing of counters: Never

 Peak input rate: 8 bytes/sec, at 2019-03-19 09:20:48

 Peak output rate: 1 bytes/sec, at 2019-03-19 09:16:16

 Last 300 second input: 0 packets/sec 0 bytes/sec -%

 Last 300 second output: 0 packets/sec 0 bytes/sec -%

 Input (total):  2892 packets, 236676 bytes

          24 unicasts, 2 broadcasts, 2866 multicasts, 0 pauses

 Input (normal):  2892 packets, - bytes

          24 unicasts, 2 broadcasts, 2866 multicasts, 0 pauses

 Input:  0 input errors, 0 runts, 0 giants, 0 throttles

          3 CRC, 0 frame, - overruns, 0 aborts

          - ignored, - parity errors

 Output (total): 29 packets, 1856 bytes

          24 unicasts, 5 broadcasts, 0 multicasts, 0 pauses

 Output (normal): 29 packets, - bytes

          24 unicasts, 5 broadcasts, 0 multicasts, 0 pauses

 Output: 0 output errors, - underruns, - buffer failures

          0 aborts, 0 deferred, 0 collisions, 0 late collisions

          0 lost carrier, - no carrier

The output shows that CRC error packets occurred at the input interface.

Common causes

·     The interface has a loose connection with the cable connector.

·     The interface has an anomaly.

·     The cable connector is damaged.

·     The transceiver module or optical fiber is contaminated or poorly connected.

·     The optical power is insufficient.

·     The intermediate link or device fails.

·     A hardware failure occurs on the device or card.

Troubleshooting flow

Figure 1 shows the troubleshooting flowchart.

Figure 1 Flowchart for troubleshooting the CRC error

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Solution

1.     Perform an internal loopback test for the interface.

Enable internal loopback by configuring the loopback internal command for the interface, and then identify whether the number of CRC error packets increases by using the display interface command. If the number increases, a device or card hardware failure might exist. In this case, contact Technical Support. If the number does not increase, the interface does not have an internal issue.

2.     Check the connection between the interface and cable connector.

a.     Check the physical connection of the interface and cable connector for loose insertion. If there is a loose connection, properly connect the interface and cable connector.

b.     Check for interface anomalies, such as foreign objects inside the interface, bent pins, or deformed interface casings. If an anomaly occurs, change another interface or replace the transceiver module.

c.     Identify whether the cable connector is damaged. Replace the cable if it is damaged.

3.     Identify whether transceiver module is abnormal.

a.     Connect the Tx and Rx ends of the transceiver module of this interface by using optical fiber, and then identify whether the number of CRC error packets increases with the <display interface command. If the number increases, the transceiver module might be faulty. If the number does not increase, the transceiver module is not faulty.

b.     Use the display transceiver alarm command to identify whether the transceiver module has Rx_Los or Tx_Fault alarm messages. If any alarm messages are present, clean or replace the optical fiber or transceiver module.

c.     Use the display transceiver diagnosis command to identify whether the Rx and Tx power of the transceiver module is within the specified upper and lower limits. If the power exceeds these limits, clean or replace the optical fiber or transceiver module.

4.     Use a normal interface to test whether the fault is cleared.

Use another normal interface for test. If no error packets occur after the interface replacement but occur again when the original interface is used, a hardware fault exists in the interface. Replace the interface and report the fault details to technical support personnel for analysis. If error packets persist even after you switch to another normal interface, a link fault in the intermediate transmission link might exist.

5.     Identify whether the intermediate transmission link is functioning correctly.

Test the intermediate link with instruments. Poor link quality or excessive signal degrade in the link can cause errors in packet transmission. Identify whether the devices (such as optical converters, patch panels, transmission devices) attached to the intermediate link are operating correctly. If the intermediate transmission link fails, replace or restore the link.

6.     Execute the shutdown command, and then execute the undo shutdown command to identify whether the interface can resume normal operation.

7.     If the issue persists, a device or card hardware failure might occur. Collect relevant information and contact Technical Support.

Related alarm and log messages

Alarm messages

N/A

Log messages

Number of CRC error packets exceeded the high threshold: Interface Name Ten-GigabitEthernet2/0/0, High threshold 1000, Number of CRC error packets 6611063, Interval 10s.

Packet receiving failure

Symptom

The interface status is UP, but the interface cannot receive packets or drops packets.

Execute the display interface command to verify that the received packet count growth on the local inbound direction is lower than the transmitted packet count growth on the peer outbound direction.

Common causes

·     The interface has CRC errors.

·     Configuration on the interface affects packet reception.

·     A hardware failure occurs on the device or card.

Troubleshooting flow

Figure 2 shows the troubleshooting flowchart.

Figure 2 Flowchart for troubleshooting packet receiving failure

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Solution

1.     Identify whether CRC errors occur on the interface.

For more information, see the procedure for troubleshooting CRC error.

2.     Identify whether the interface configuration affects packet reception.

Identify whether the interface configuration affects packet reception by following these steps:

¡     Execute the display interface brief command to check for any anomalies in the interface configuration. The configuration includes duplex mode, VLAN, and interface type settings on both ends. If an anomaly occurs, edit the interface attribute configuration to identify whether the faulty interface can resume normal operation. If the issue persists, execute the shutdown command, and then execute the undo shutdown command to identify whether the interface can resume normal operation.

¡     For a Layer 2 interface with STP enabled, use the display stp brief command to identify whether the interface is in discarding state. If the interface is set to discarding state by STP, further troubleshoot the issue according to the STP configuration. As a best practice, configure the interface connected to endpoint device as an edge port or disable the STP feature on that interface.

¡     If the interface has joined an aggregation group, use the display link-aggregation summary command to check whether it is in the Selected state. When the interface state is Unselected, the interface cannot send or receive packets. Locate the cause of the interface being in the Unselected state. If the attribute configuration of the member interface in the aggregation group does not match the reference interface, further troubleshoot the issue.

¡     If ACL filtering is configured, further troubleshoot based on the ACL configuration.

3.     Execute the shutdown command, and then execute the undo shutdown command to identify whether the interface can resume normal operation.

4.     If the issue persists, a device or card hardware failure might occur. Collect relevant information and contact Technical Support.

Related alarm and log messages

Alarm messages

N/A

Log messages

N/A

Packet sending failure

Symptom

The interface status is UP, but the interface cannot send packets.

Execute the display interface command to verify that the sent packet count does not increase in the local outbound direction.

Common causes

·     The transceiver module is faulty.

·     Configuration on the interface affects packet reception.

·     A hardware failure occurs on the device or card.

Troubleshooting flow

Figure 3 shows the troubleshooting flowchart.

Figure 3 Flowchart for troubleshooting packet receiving failure

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Solution

1.     Perform an internal loopback test for the interface.

Enable internal loopback by configuring the loopback internal command for the interface, and then identify whether the number of sent packets increases in the local outbound direction by using the display interface command. If the number does not increase, a device or card hardware failure might exist. In this case, contact Technical Support. If the number increases, the interface does not have an internal issue.

2.     Identify whether the interface configuration affects packet sending.

Identify whether the interface configuration affects packet sending by following these steps:

¡     For a Layer 2 interface with STP enabled, use the display stp brief command to identify whether the interface is in discarding state. If the interface is set to discarding state by STP, further troubleshoot the issue according to the STP configuration. As a best practice, configure the interface connected to endpoint device as an edge port or disable the STP feature on that interface.

¡     If the interface has joined an aggregation group, use the display link-aggregation summary command to check whether it is in the Selected state. When the interface state is Unselected, the interface cannot send or receive packets. Locate the cause of the interface being in the Unselected state. If the attribute configuration of the member interface in the aggregation group does not match the reference interface, further troubleshoot the issue.

¡     If ACL filtering is configured, further troubleshoot based on the ACL configuration.

¡     Identify whether the interface is configured to block broadcast/unknown multicast/unknown unicast packets in the outbound direction. Some protocols (such as ARP, DHCP, RIP, and IGMP) exchange broadcast/unknown multicast/unknown unicast packets during operation. If this feature is enabled, these protocol packets cannot be sent through the interface. Disable this feature and identify whether the faulty interface can resume normal operation.

3.     Execute the shutdown command, and then execute the undo shutdown command to identify whether the interface can resume normal operation.

4.     If the issue persists, a device or card hardware failure might occur. Collect relevant information and contact Technical Support.

Related alarm and log messages

Alarm messages

N/A

Log messages

N/A

Copper interface failure to come up

Symptom

After you connect the copper interface with a cable, the interface fails to come up.

Common causes

The following are the common causes of this type of issue:

·     The port configuration is faulty.

·     The cable is faulty.

·     The local or peer interface is faulty.

Troubleshooting flow

Figure 4 shows the troubleshooting flowchart:

Figure 4 Flowchart for troubleshooting packet receiving failure

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Solution

1.     Identify whether the settings (such as port speed, duplex, negotiation and mode) are consistent for the interfaces on both ends of the cable. Execute the display interface brief command to identify whether the port speed and duplex configuration match on both ends. If they do not match, configure the port speed and duplex mode by using the speed and duplex commands.

<Sysname> display interface brief

Brief information on interfaces in route mode:

Link: ADM - administratively down; Stby - standby

Protocol: (s) – spoofing

 

Interface            Link Protocol Primary IP      Description

XGE2/0/0             DOWN DOWN     --

Loop0                UP   UP(s)    2.2.2.9

NULL0                UP   UP(s)    --

Vlan1                UP   UP       --

Vlan999              UP   UP       192.168.1.42

 

Brief information on interfaces in bridge mode:

Link: ADM - administratively down; Stby - standby

Speed: (a) - auto

Duplex: (a)/A - auto; H - half; F - full

Type: A - access; T - trunk; H - hybrid

Interface         Link    Speed   Duplex   Type   PVID  Description

XGE2/0/0          DOWN    auto     A        A      1    aaaaaaa

XGE2/0/1           UP     10G(a)   F(a)     A      1    aaaaaaa

2.     Check the port status with the display interface command. Identify whether the Current state field is Administratively DOWN. If so, activate the corresponding Ethernet port with the undo shutdown command.

<Sysname> display interface ten-gigabitethernet 2/0/0

Ten-GigabitEthernet2/0/0

Current state: Administratively DOWN

Line protocol state: DOWN

Description: Ten-GigabitEthernet2/0/0 Interface

Bandwidth: 1000000 kbps

Maximum transmission unit: 1500

Allow jumbo frames to pass

Broadcast max-ratio: 100%

Multicast max-ratio: 100%

Unicast max-ratio: 100%

Internet protocol processing: Disabled

...

3.     Replace with a good network cable and identify whether the issue is resolved.

4.     Replace the local device port and the remote device port separately to identify whether the issue is resolved.

5.     If the issue persists, collect the following information and contact Technical Support:

¡     Results of the each step.

¡     Configuration data, log messages, and alarm information.

Related alarm and log messages

Alarm messages

N/A

Log messages

N/A

Frequent UP and DOWN states

Symptom

After you insert a cable or transceiver module into the card, the interface frequently comes up and goes down.

Common causes

The following are the common causes of this type of issue:

·     The transceiver module or cable is faulty.

·     The copper interface auto-negotiation is unstable.

·     The WAN interface clock configuration is faulty on both ends.

Troubleshooting flow

Figure 5 shows the troubleshooting flowchart:

Figure 5 Flowchart for troubleshooting packet receiving failure

‌

Solution

1.     For a fiber interface, identify whether the transceiver module is faulty. Check the alarm information of the transceiver module to troubleshoot issues with both modules and the intermediate optical fiber connection. If the alarm message indicates an issue on the receiving end, it is typically caused by the peer port, optical fiber, or intermediate transmission device. If the sending end is faulty, or the current or voltage is abnormal, check the local interface.

<Sysname> display transceiver alarm interface ten-gigabitethernet 2/0/0

Ten-GigabitEthernet2/0/0 transceiver current alarm information:

  RX loss of signal

  RX power low

2.     Identify whether the Rx and Tx optical power of the transceiver module is normal (within the upper and lower thresholds of the module's optical power). If the Tx optical power is at a critical value, replace the fiber and transceiver module for cross-verification. If the Rx optical power is at a critical value, check the peer transceiver module and intermediate fiber link.

<Sysname> display transceiver diagnosis interface ten-gigabitethernet 2/0/0

Ten-GigabitEthernet2/0/0 transceiver diagnostic information:

  Current diagnostic parameters:

    Temp(°C)  Voltage(V)  Bias(mA)  RX power(dBm)  TX power(dBm)

    36        3.31        6.13      -35.64          -5.19

  Alarm thresholds:

           Temp(°C)   Voltage(V)  Bias(mA)  RX power(dBM)  TX power(dBM)

    High   50         3.55        1.44      -10.00         5.00

    Low    30         3.01        1.01      -30.00         0.00

3.     For a copper interface, unstable negotiation typically occurs during auto-negotiation. In such cases, try setting a forced speed and duplex.

4.     For a WAN interface, identify whether the clock is configured on both ends. Configure the end where the MPU has a clock daughter card as master and the other end as slave.

5.     If the issue persists, check the link, peer device, and intermediate device.

6.     If the issue persists, collect the following information and contact Technical Support:

¡     Results of the each step.

¡     Configuration data, log messages, and alarm information.

Related alarm and log messages

Alarm messages

N/A

Log messages

N/A