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AR Router Troubleshooting Guide

This Product Documentation provides guidance for maintaining AR Enterprise Router, covering common information collection and fault diagnostic commands, typical fault troubleshooting guide, and troubleshooting.
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Next Hop of the Incoming Traffic Changes After a Master/Slave Switchover of the Attached Non-Huawei Devices

Next Hop of the Incoming Traffic Changes After a Master/Slave Switchover of the Attached Non-Huawei Devices

Fault Symptom

As shown in Figure 19-15, VRRP is configured on Router A and Router B. Router A and Router B are connected through a heartbeat link. The other devices are all non-Huawei devices. Router C and Router D, which are attached to Router A and Router B, respectively, are load-balancing devices and provide redundancy for each other. A routing policy is configured on the interface that connects Router A to Router C to enable incoming traffic to be forwarded by the specified interface and specifies Router G as the next hop.

After the master device Router C becomes faulty, CPU usage on Router C reaches 100%. Because redundancy backup and automatic master/slave switchover are configured, incoming traffic is switched to Router D. However, the next hop of the incoming traffic on Router A is Router E. Therefore, the incoming traffic is not forwarded to the next hop specified by the configured routing policy.

Figure 19-15 Change in the next hop of incoming traffic

Fault Analysis

After a master/slave switchover of the non-Huawei devices, the path of incoming traffic is Router D->Router B->heartbeat link->Router A. Because route redirection is not configured on the interface of the heartbeat link, the next hop of the incoming traffic is not Router G as specified but Router E. This indicates that the configured routing policy becomes invalid.

To clear the fault, configure a routing policy on the interface of the heartbeat link between Router A and Router B to enable incoming traffic to be forwarded along the specified path, which is the same as the path before the master/slave switchover. That is, configure route redirection on the interface of the heartbeat link to forcibly change the next hop of the incoming traffic to Router G.

Procedure

  1. Run the system-view command on Router A to enter the system view.
  2. Configure an ACL rule.

    1. Run the aclnumber acl-number command to create an ACL and enter the ACL view.
    2. Run the rule command to configure an ACL rule.
    3. Run the quit command to quit the ACL view.

  3. Match the ACL rule for route redirection.

    1. Run the traffic classifier classifier-name operator or command to define a traffic classifier and enter the traffic classifier view.
    2. Run the if-match acl acl-number command to match the ACL.
    3. Run the quit command to quit the traffic classifier view.
    4. Run the traffic behavior behavior-name command to define a traffic behavior and enter the traffic behavior view.
    5. Run the redirect ip-nexthop ip-address command to perform route redirection, specifying the next-hop address as the address of the interface that connects Router G to Router A.
    6. Run the quit command to quit the traffic behavior view.
    7. Run the traffic policy policy-name command to define a traffic policy and enter the traffic policy view.
    8. Run the classifier classifier-name behavior behavior-name command to specify a traffic behavior for the traffic classifier in the traffic policy.

  4. Apply the traffic policy to the interface of the heartbeat link on Router A.

    1. Run the interface eth-trunk trunk-id command to enter the view of the interface of the heartbeat link.
    2. Run the traffic-policy policy-name inbound command to apply the traffic policy.

  5. Run the display ip routing-table command to check incoming traffic of Router A. The next hop of the incoming traffic is Router G. This indicates that the fault is cleared.

Summary

After a master/slave switchover is performed on network devices, pay attention to the impact of the switchover on network traffic.

If incoming traffic fails to be forwarded along the path specified by the configured routing policy, configure route redirection to specify the next hop of a link to solve the problem.

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Updated: 2019-08-09

Document ID: EDOC1000079719

Views: 493200

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