I. Description of the phenomenon and problem

The service interruption of the second GE port on the Huawei OSN3500 N2EGS2 single board is not restored during the supporting upgrade network, and the service is restored by modifying the operating mode of this GE ( 1000mfull->self-negotiation ).

II. Version Information

Network management version: T2000V2R6C01Cspc001

Host version: 5.21.17.31

Huawei SSN2EGS2single board version: 5.30T03

III. Problem localization process and cause analysis:

According to the fault phenomenon and service recovery operation feedback from users, it can be judged as a port negotiation problem. Through the confirmation of the MO and the collection of data, it is also basically confirmed that the occurrence of such failures is caused by abnormal working mode negotiation. Since the docking equipment is not from other vendors, it is not possible to confirm the working mode of the docking port, and there are two situations in practical applications:

1, before upgrading, the working modes of the two ends do not match: in the case of mismatched working modes of the docking ports, there is still a small probability that the negotiation will be normal, but most of the time the negotiation is unsuccessful. As upgrading the EGS2 board will hard reset the board, which will inevitably lead to the port to reproduce the negotiation, and thus the negotiation will be unsuccessful due to the mismatch of the port's working mode;

2、During the upgrade process, the working mode of the docking device is changed: the hard reset of the EGS2 single-board upgrade will reproduce the negotiation, and the negotiation fails due to the inconsistency of the working mode.

And the current confirmation data: when the user modifies the working mode of IP2 from 1000 full-duplex -> self-negotiation, it is found that the port negotiation is successful, and the result of the negotiation is 1000MFULL.

For the first possible scenario, we have done several simulations in the lab, here is the simulation process:

Use the SmartBits port to simulate the docking device, the IP2 of the EGS2 single board is docked with the SmartBits port, and the working mode of the SmartBits port is auto mode (as in Figure 1 )

IP2 of theEGS2single board is set to 1000mfull (as in Figure 2 )

After several attempts, the port negotiation finally succeeds in the case of inconsistent working mode (as in Figure 3 ), upgrading the EGS2 single-board software to reset the single-board, and the port negotiation fails when the single-board is reset (as in Figure 4 ). Negotiation was successful after changing the IP2 working mode to auto mode.

At the same time, weverify the upgrade softwarein the case of consistent working mode (self-negotiation) of the docking port (as in Figure5), the negotiation result before the single board upgrade (as in Figure6) and the negotiation result after the upgrade (as in Figure7) are both successful.

IV. Conclusions of the problem analysis

This problem is caused by inconsistent configuration of the working mode of the docking port.

V. Emergency Recovery Measures

Modify the port working mode.

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