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ME60 Troubleshooting Guide V1.0 (VRPv8)

This document provides the maintenance guide of the device, including daily maintenance, emergence maintenance, and typical troubleshooting.
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
IPv6 Forwarding Troubleshooting

IPv6 Forwarding Troubleshooting

This chapter describes common causes of IPv6 forwarding faults, and provides the corresponding troubleshooting flowcharts, troubleshooting procedures, alarms, and logs.

IPv6 Address Conflicts Occur on Interfaces

This section describes the troubleshooting flowchart and provides a step-by-step troubleshooting procedure for IPv6 address conflicts on interfaces.

Common Causes
This fault is most commonly caused due to the following reasons:
  • Directly connected interfaces are configured with the same IPv6 address.

  • A local Ethernet interface is configured with the local loopback function before being configured with an IPv6 address.

Troubleshooting Flowchart

Figure 4-36 shows the troubleshooting flowchart for IPv6 address conflicts on interfaces.

Figure 4-36 Troubleshooting flowchart for IPv6 address conflicts on interfaces

Troubleshooting Procedure
Context
NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

  • In immediate validation mode, the configurations take effect after the commands are entered.
  • In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

  1. Check whether the interface where the fault occurs is an Ethernet interface.

    • If the interface is an Ethernet interface, check whether the interface is configured with the local loopback function before being configured with the IPv6 address.
      • If the interface is configured with the local loopback function before being configured with the IPv6 address, run the following commands in sequence and go to Step 2.
        1. Run the undo loopback command to disable the loopback function on the Ethernet interface.

        2. Run the undo ipv6 enable command to disable the IPv6 function on the Ethernet interface.

        3. Run the ipv6 enable command to re-enable the IPv6 function on the Ethernet interface.

        4. Run the ipv6 address { ipv6-address prefix-length | ipv6-address/prefix-length } command to reconfigure the IPv6 address on the Ethernet interface.

        5. Run the loopback local command to reconfigure the local loopback function on the Ethernet interface.

      • If the interface is configured with the loopback function after being configured with the IPv6 address, go to Step 2.

    • If the interface is not an Ethernet interface, go to Step 2.

  2. Run the undo ipv6 address command in the interface view to delete the IPv6 address configured for the interface, and run the ipv6 address command to configure a new IPv6 address in the same network segment for the interface. Go to Step 3.
  3. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.

    • If the IPv6 address is followed by [DUPLICATED], the IPv6 address is not in the normal state. Go to Step 4.

    • If the IPv6 address is not followed by [DUPLICATED], go to Step 5.

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

    • Results of this operation procedure
    • Configuration files, log files, and alarm files

  5. End.
Relevant Alarms and Logs
Relevant Alarms

None

Relevant Logs

ND/4/ADDR_DUPLICATE

ND Entries Cannot Be Learned

This section describes the troubleshooting flowchart and provides a step-by-step troubleshooting procedure for the fault that prevents ND entries from being learned.

Common Causes
This fault is most commonly caused due to the following reasons:
  • The physical status of the interface is not Up.

  • The IPv6 address is not in the normal state.

  • NS packets fail to be sent out.

  • NA packets fail to be received.

  • The number of configured ND entries exceeds the upper limit.

Troubleshooting Flowchart

Figure 4-37 shows the troubleshooting flowchart for a failure in learning ND entries.

Figure 4-37 Troubleshooting flowchart for a failure in learning ND entries

Troubleshooting Procedure
Context
NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

  • In immediate validation mode, the configurations take effect after the commands are entered.
  • In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

  1. Run the display this command in the interface view to check whether the interface is enabled with the IPv6 function.

    • If ipv6 enable is displayed in the command output, the interface is enabled with the IPv6 function. Go to Step 2.

    • If ipv6 enable is not displayed, the interface is not enabled with the IPv6 function. Run the ipv6 enable command to enable the IPv6 function and go to Step 2.

  2. Run the display ipv6 interface interface-type interface-number command to check whether the physical status of the interface is Up.

    • If the physical status of the interface is Administratively DOWN, run the undo shutdown command in the interface view and go to Step 3.

    • If the physical status of the interface is DOWN, a fault has occurred on the physical connection of the interface. Rectify the fault and go to Step 3.

    • If the physical status of the interface is UP, go to Step 3.

  3. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.

    • If the IPv6 address is in the normal state, that is, the IPv6 address is not followed by [TENTATIVE] or [DUPLICATED], go to Step 4.

    • If the IPv6 address is followed by [DUPLICATED], go to IPv6 Address Conflicts Occur on Interfaces.

    • If the IPv6 address is followed by [TENTATIVE], the IPv6 address is being detected. If the IPv6 address is being detected for a long period, perform the following steps:
      1. Run the ipv6 nd ns retrans-timer interval command to shorten the interval at which the system sends ND packets. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.
        • If the IPv6 address is in the normal state, go to Step 4.

        • If the IPv6 address is followed by [DUPLICATED], go to IPv6 Address Conflicts Occur on Interfaces.

        • If the IPv6 address is followed by [TENTATIVE], go to Step b.

      2. Run the display ipv6 interface interface-type interface-number command to check the number of DAD attempts.
        • If the number of DAD attempts is high, run the ipv6 nd dad attempts value command to reduce the number. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.
          • If the IPv6 address is in the normal state, go to Step 4.

          • If the IPv6 address is followed by [DUPLICATED], go to IPv6 Address Conflicts Occur on Interfaces.

          • If the IPv6 address is followed by [TENTATIVE], go to Step 7.

        • If the number of DAD attempts is set properly, go to Step 4.

  4. Run the display ipv6 neighbors command to check whether the number of configured ND entries has exceeded the upper limit.

    NOTE:
    The upper limit of ND entries is as follows:
    • The maximum number of dynamic and static ND entries is 16384.

    • The maximum number of dynamic ND entries learned by an interface is 4096.

    • The maximum number of static ND entries learned by an interface is 300.

    • If the number of ND entries does not exceed the upper limit, go to Step 5.

    • If the number of ND entries exceeds the upper limit, go to Step 7.

  5. Determine whether the packets are discarded in the receiving or sending direction and where the packets are discarded.

    Run the reset ipv6 statistics command on the source and destination ends to delete IPv6 statistics, then run the ping ipv6 command and the display icmpv6 statistics [ interface interface-type interface-number ] command again to view the statistics on the received and sent ICMPv6 packets on the interface.
    • If the Neighbor solicit value in the Sent packets field does not increase on the source end, the source end has not sent any Neighbor Solicitation (NS) packets. Go to Step 6.

    • If the Neighbor solicit value in the Sent packets field increases but the Neighbor advert value in the Received packets field does not increase on the source end, and both the Neighbor advert value in the Sent packets field and the Neighbor solicit value in the Received packets field do not increase on the destination end, the destination end has not received the NS packets sent by the source end. Go to Step 6.

    • If the Neighbor solicit value in the Sent packets field increases but the Neighbor advert value in the Received packets field does not increase on the source end, and the Neighbor solicit value in the Received packets field increases but the Neighbor advert value in the Sent packets field does not increase on the destination end, the source end has sent the NS packets, and the destination end has received them but has failed to reply with Neighbor Advertisement (NA) packets. Go to Step 6.

    • If the Neighbor solicit value in the Sent packets field increases but the Neighbor advert value in the Received packets field does not increase on the source end, and both the Neighbor advert value in the Sent packets field and the Neighbor solicit value in the Received packets field increase on the destination end, the source end has sent the NS packets, and the destination end has received them and has replied with the NA packets. Go to Step 6.

    • If both the Neighbor solicit value in the Sent packets field and the Neighbor advert value in the Received packets field increase on the source end, and both the Neighbor advert value in the Sent packets field and the Neighbor solicit value in the Received packets field increase on the destination end, the source end has sent the NS packets and received the NA packets from the destination end. Go to Step 7.

  6. Determine where the packets are discarded.

    Locate the position based on the direction in which the fault occurs. Perform the following operations to enable ND packet debugging:
    NOTE:

    Enabling debugging affects system performance. Exercise caution when enabling debugging.

    <HUAWEI> debugging ipv6 nd packet
    <HUAWEI> terminal debugging

    Run the ping ipv6 -c echo-number destination-ipv6-address command to send a ping packet. Check whether the source end has sent an NS packet and received an NA packet, and whether the destination end has received an NS packet and replied with an NA packet. If no information about packet sending and receiving is displayed, go to Step 7.

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

    • Results of this operation procedure

    • Configuration files, log files, and alarm files

  8. End.
Relevant Alarms and Logs
Relevant Alarms

None

Relevant Logs

ND/4/ADDR_DUPLICATE

IPv6 Addresses of Neighbors Cannot Be Pinged

This section describes the troubleshooting flowchart and provides a step-by-step troubleshooting procedure for the fault that prevents the IPv6 address of a neighbor from being pinged.

Common Causes
This fault is most commonly caused due to the following reasons:
  • The physical status of the interface is not Up.

  • The IPv6 address is not in the normal state.

  • The link transmission delay is too long. The source end, therefore, cannot receive a response packet from the destination end within the waiting time.

  • A hardware fault occurs.

Troubleshooting Flowchart

Figure 4-38 shows the troubleshooting flowchart an IPv6 ping failure.

Figure 4-38 Troubleshooting flowchart for an IPv6 ping failure

Troubleshooting Procedure
Context
NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

  • In immediate validation mode, the configurations take effect after the commands are entered.
  • In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

  1. Run the display this command in the interface view to check whether the interface is enabled with the IPv6 function.

    • If the ipv6 enable field is displayed, the interface is enabled with the IPv6 function. Go to Step 2.

    • If the ipv6 enable field is not displayed, the interface is not enabled with the IPv6 function. Run the ipv6 enable command to enable the IPv6 function and go to Step 2.

  2. Run the display ipv6 interface interface-type interface-number command to check whether the physical status of the interface is Up.

    • If the physical status of the interface is Administratively DOWN, run the undo shutdown command in the interface view and go to Step 3.

    • If the physical status of the interface is DOWN, a fault has occurred on the physical connection of the interface. Rectify the fault and go to Step 3.

    • If the physical status of the interface is UP, go to Step 3.

  3. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.

    • If the IPv6 address is in the normal state, that is, the IPv6 address is not followed by [TENTATIVE] or [DUPLICATED] in the command output, go to Step 4.

    • If the IPv6 address is followed by [DUPLICATED], go to IPv6 Address Conflicts Occur on Interfaces.

    • If the IPv6 address is followed by [TENTATIVE], the IPv6 address is being detected. If the IPv6 address is being detected for a long period, perform the following steps:
      1. Run the ipv6 nd ns retrans-timer interval command to shorten the interval at which the system sends ND packets. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.
        • If the IPv6 address is in the normal state, go to Step 4.

        • If the IPv6 address is followed by [DUPLICATED], go to IPv6 Address Conflicts Occur on Interfaces.

        • If the IPv6 address is still followed by [DUPLICATED], go to Step 6.

      2. Run the display ipv6 interface interface-type interface-number command to check the number of DAD attempts.
        • If the number of DAD attempts is high, run the ipv6 nd dad attempts value command to reduce the number. Run the display ipv6 interface interface-type interface-number command to check whether the IPv6 address is in the normal state.
          • If the IPv6 address is in the normal state, go to Step 4.

          • If the IPv6 address is followed by [DUPLICATED], go to IPv6 Address Conflicts Occur on Interfaces.

          • If the IPv6 address is followed by [TENTATIVE], go to Step 8.

        • If the number of DAD attempts is set properly, go to Step 4.

  4. Check IPv6 routing entries.

    Run the display ipv6 routing-table command on the source end to check whether the source end has a route to the destination end and on the destination end to check whether the destination end has a route to the source end.
    • If the source end does not has a route destined to the destination end, or the destination end does not has a route destined to the source end, configure a routing protocol for or add a static route to the source end or the destination end. Go to Step 5.

    • If the source and destination ends have routes to each other, go to Step 5.

  5. Run the display ipv6 neighbors command to check the ND entries on the interface.

    • If there is no ND entry about the neighbor, the local end failed to learn the ND entries of the neighbor. Go to ND Entries Cannot Be Learned.

    • If information about the ND entries is correct, go to Step 6.

  6. Determine whether the packets are discarded in the receiving or sending direction and where the packets are discarded.

    Run the reset ipv6 statistics command on the source and destination ends to delete the IPv6 statistics, and run the ping ipv6 command and the display icmpv6 statistics [ interface interface-type interface-number ] command again to view the statistics on the received and sent ICMPv6 packets on the interface.
    • If the Echoed value in the Sent packets field does not increase on the source end, the source end has not sent any IPv6 packets to the destination end. Go to Step 7.

    • If the Echoed value in the Sent packets field increases but the Echo replied value in the Received packets field does not increase on the source end, and both the Echo replied value in the Sent packets field and the Echoed value in the Received packets field do not increase on the destination end, the destination end has not received the IPv6 packets sent by the source end. Go to Step 7.

    • If the Echoed value in the Sent packets field increases but the Echo replied value in the Received packets field does not increase on the source end, and the Echoed value in the Received packets field increases but the Echo replied value in the Sent packets field does not increase on the destination end, the source end has sent the IPv6 packets, and the destination end has received the IPv6 packets but has failed to send any response packets. Go to Step 7.

    • If the Echoed value in the Sent packets field increases but the Echo replied value in the Received packets field does not increase on the source end, and both the Echo replied value in the Sent packets field and the Echoed value in the Received packets field increase on the destination end, the source end has sent the IPv6 packets but has failed to receive any response packets from the destination end. Go to Step 7.

    • If both the Echoed value in the Sent packets field and the Echo replied value in the Received packets field increase on the source end, and both the Echo replied value in the Sent packets field and the Echoed value in the Received packets field increase on the destination end, the source end has sent the IPv6 packets and received the response packets from the destination end. The fault that prevents the IPv6 address of the neighbor from being pinged may be caused by an excessively long link transmission delay. Run the ping ipv6 -t timeout command to increase the timeout period for sending an ICMPv6 response packet.
      • If the ping succeeds, go to Step 9.

      • If the ping still fails, go to Step 7.

  7. Determine where the packets are discarded.

    Perform the following operations to enable IPv6 packet debugging.
    NOTE:

    Enabling debugging affects system performance. Exercise caution when enabling debugging.

    <HUAWEI> debugging rawip ipv6 packet
    <HUAWEI> debugging ipv6 packet
    <HUAWEI> terminal debugging

    Run the ping ipv6 -c echo-number destination-ipv6-address command to send five ping packets. Check whether the source end has sent five packets and received five response packets, and whether the destination end has received five packets and sent five response packets. If no related information is displayed, go to Step 8.

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

    • Results of this operation procedure

    • Configuration files, log files, and alarm files

  9. End.
Relevant Alarms and Logs
Relevant Alarms

None

Relevant Logs

None

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Updated: 2019-06-11

Document ID: EDOC1000175918

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