Huawei V200R001C01 - Interface Backup Troubleshooting

11.1 Interface Backup Troubleshooting
11.1.1 Interface Backup Fails to Take Effect
Common Causes
As shown in Figure 11-1, RouterA and RouterB are connected.
Multiple interfaces on RouterA back up one another:
l Interface1 is the primary interface.
l Interface2 and interface3 are backup interfaces.
Figure 11-1 Networking diagram of interface backup
LAN2LAN1
interface1
interface2
interface3
RouterA RouterB
Interface backup cannot take effect in the following situations:
l Backup interfaces become unavailable after the primary interface fails.
l In load balancing mode, load balancing cannot be implemented among the primary and
backup interfaces because they cannot all be in Up state simultaneously.
l In load balancing mode, traffic cannot be load balanced among multiple interfaces.
This fault is commonly caused by one of the following:
l The physical status of backup interfaces is Down.
l The link layer status of backup interfaces is Down.
l In load balancing mode:
– The load balancing threshold and maximum bandwidth are not configured for the
primary interface.
– An equal-cost route is not generated.
– Only one flow needs to be transmitted.
Troubleshooting Flowchart
Figure 11-2 shows the troubleshooting flowchart.
Huawei AR2200-S Series Enterprise Routers
Troubleshooting 11 Reliability
Issue 01 (2012-01-06) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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