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Knowledge Base

Packet Loss Occurs When a Huawei S12708 Is Connected to an H3C S10500

Publication Date:  2019-05-15  |   Views:  191  |   Downloads:  0  |   Document ID:  EKB1100015264


Issue Description

1.Onsite environment

Based on the onsite environment, the main network environment is described as follows:

The H3C S10500 functions as the core switch, and the Huawei S12708 functions as the aggregation switch. The two devices are connected through 40GE ports, and the S12708 is connected to two access switches (S5700s) and servers.

2. Related problems

        (1) A large number of packets will be lost when terminals at both ends ping each other.

        (2) Two switches are directly connected. After the ping command is run on the switch, packet loss still occurs.

        (3) When the S5700s connected to the S12708 are directly connected to the core switch S10500, and the ping operation is performed on the terminal, no packet loss occurs.

Handling Process

(1) Check the physical connection of the device. It is found that the packet loss is not caused by the loop. (2) Check the hardware status of the device. It is found that the hardware status is normal and no exception occurs.

(3) Collect the diagnostic log information of the device and check recent operations of the device. No violation occurs, and the log information of the device is normal.

(4) Replace the optical module and optical fiber. The media is normal.

(5) Change the cable between the S12708 and S10500 to the cable of the 10GE card. Configure the cable to ensure that the link is normal. Run the ping command. It is found that packet loss still occurs.

(6) Perform traffic statistics collection on uplink and downlink interfaces of the S12708. The statistics are mainly about ICMP packets. The result shows that only unidirectional data flows pass through the two interfaces.

(7) According to the log information, the aggregated interfaces directly connected to the two switches receive a large number of BPDUs. After communication with the R&D engineers, it is recommended that you disable the spanning tree protocol and then run the ping command. The data forwarding on the interfaces is normal. No packet loss occurs and the problem is solved.

Root Cause

The spanning tree protocol is incompatible between different vendors.


No physical loop exists on site. The spanning tree protocol of Huawei S12708 switch is disabled. No packet loss occurs and the problem is solved


STP is disabled on Huawei S12708 based on onsite situation. The reason is that STP convergence may be different when Huawei devices are interconnected with third-party devices. When two vendors interconnect with each other, STP convergence occurs. During STP convergence, the interface does not forward traffic. Therefore, packet loss occurs. After the convergence is complete, the fault is rectified. If convergence is performed periodically and BPDUs are continuously sent, this problem will occur.