Service Interruption Caused by Replacement of MABH Subracks
Summary: A 19-inch subrack on the MA5600T is replaced with a subrack that has a different PCB pversion after configuration data is saved on the main control board. Although the system starts up
normally, service interruption occurs on the MA5600T after the board replacement because the LSW
chip port numbers on the backplane with a different PCB version are different.
[Problem Description]
Trigger conditions:
A subrack on the MA5600T is replaced with a subrack that has a different PCB version after
configuration data is saved on the main control board.
Symptom:
After the subrack replacement, the system can start up but services of slots 1–4 are interrupted.
Identification method:
Method 1: Run commands to check the backplane type of subracks. If the PCB version of the new
subrack is different from that of the original subrack, services are affected. As shown in the following
message, the PCB version is VER C which is different from that of the original subrack whose PCB
version is VER B.
MA5600T(config)#display version backplane 0
Backplane: H801MABH
-----------------------------------------
PCB Version: H801MABH VER C
MAB Version: 0001
Board Type: 8
Method 2: Remove boards in slots 10–16 from the subracks and check the PCB silk screens on the backplanes. If the PCB versions are
different, as shown in the following two figures, services will be affected after subrack replacement.
Silk screen of PCB version on backplane
[Root Cause]
Hardware on the MABH backplane is upgraded. The PCB version is upgraded to VER C from
VER B. Port numbers of the LSW chip on the main control board and slots 1–4 on the MABH
backplane are adjusted to enhance the bandwidth processing capability of the MABH backplane
and ensure good signal quality. Because service configuration is related to LSW ports, data saved
on the backplane of VER B version cannot be directly used on the backplane of VER C version.
[Impact and Risk]
Services are affected although the system can start up.
[Measures and Solutions]
Recovery measures:
Measure 1: Replace the subrack with a subrack that has the same PCB version.
Measure 2: After the system starts up, run the following command to restore data and generate new
data files.
MA5600T(config)#active configuration system
System will reboot after this command, continue? (y/n)[n]:y
Note: The command execution duration depends on the number of configured services on the live
network. More services require a longer duration. Usually, it takes about 1 hour. The execution
duration will not exceed 3 hours.
Preventive measures:
When a subrack needs to be replaced, replace it with a subrack that has the same backplane version.
Solution:
Release new versions for smooth switch. The plan for new versions is as follows:
R007 version: V800R007C00SPC313 which is to be released in May
R008 version: V800R008C00SPC312 which is to be released in April
R009 version: V800R009C00SPC106 which is to be released in May
R010 version: V800R010C00SPC102 which is to be released in July
[Rectification Scope and Time Requirements]
No rectification is required.
[Rectification Instructions]
No rectification is required.
[Attachment]
No attachment is provided.
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