[Problem Description]
Trigger conditions:
A linear or ring MSP switching on STM-64 Boards is triggered by an SF event (R_LOS, R_LOF, or MS_AIS) and the SF event lasts for less than 10 ms.
Fault symptom:
After the SF event clears, the MSP protocol changes to the normal state, but is on the idle state page (without the MS_APS_INDI_EX alarm) at one end and on the switching state page (with the MS_APS_INDI_EX alarm) at the other end. The services are interrupted thus cannot be restored and need upgrading by Huawei engineers.Or you can sell another one on Huawei network product distributors.
Identification method:
1. Check whether boards of “involved versions” are used and whether the problem symptoms are as described in this document.
2. Check whether any of the following boards exists in the switched span: SSN1SL64, SSN1SF64, SSN3SL64, and SSN1SLD64 and whether the board software version is 7.15.
3. Check the K byte event, and confirm that the when the SF event end, the EVENT-PARA of K_RECEIVED is the same the one before.
PG-ID EVENT-NO EVENT-VALUE EVENT-PARA DATE-TIME TIME-STAMP
2 598 K_RECEIVED 0x0540 2012-01-13 01:54:09 0x00ec58c4
2 599 K_DIR 0x0000 2012-01-13 01:54:09 0x00ec58cd
2 618 K_RECEIVED 0xb54a 2012-02-10 17:38:32 0x0163e7fd
2 619 K_DIR 0x0002 2012-02-10 17:38:32 0x0163e806
2 620 SF_CLEARS 0x0000 2012-02-10 17:43:02 0x021df4d6
2 621 K_RECEIVED 0x0540 2012-02-10 17:43:02 0x021df616
2 622 K_DIR 0x0000 2012-02-10 17:43:02 0x021df61f
As the K byte event above, the west side receive a K byte (0x0540), at the same time, the other NE which MSP switch happened don’t sent this K byte, also this K byte (0x0540) was received before.
[Root Cause]
When an SF event is transiently reported, an exception occurs when the board of an “involved version” processes the K byte. That is, the board incorrectly reports the history K byte to the MSP protocol. As a result, the MSP protocol goes abnormal and services are interrupted.
[Impact and Risks]
The MSP switching fails and services are interrupted.
[Measures and Solutions]
Recovery measures:
Restart the MSP protocol.
Solutions:
1.Load the V1R8C02SPH201 hot patch to the line boards.
2.Upgrade to R8C02SPC300 and later version or choose a new one in excellent Huawei network product ditributor.
[Rectification Guide]
It is recommended that you load the hot patch to the line boards to resolve this problem. For details, see the OptiX NG-SDH Hot Patch Upgrade-20120625-A
For the software upgrade method, refer to the corresponding software upgrade guide.
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