When Incorrect Fan Rotation Speed Adjustment of the OptiX OSN NG WDM Products

Keywords: WDM products,OptiX OSN NG WDM

Summary:

For the OptiX OSN NG WDM of a version earlier than V100R006C01SPC200, subrack temperature

detection is implemented by the SCC board in the larger-number slot. It is implemented by the SCC

board in the smaller-number slot only when the SCC board in the larger-number slot is asserted

offline. The fan rotation speed control however, is always implemented by the active SCC board

based on its obtained subrack temperature. When the active SCC board is the SCC board in the

smaller-number slot, the fan rotation speed does not match with the subrack temperature.

 

[Problem Description]

Trigger condition:

When all the following conditions are met, the problem will occur:

1. The NE is an OptiX OSN NG WDM NE.

2. The NE version is earlier than V100R006C01SPC200.

Involved mainstream versions are as follows:

OptiX OSN 6800/3800 V100R004C04SPC800

OptiX OSN 8800 V100R002C02SPC800

OptiX OSN 8800/6800/3800 V100R005C00SPC700

OptiX OSN 8800/6800/3800 V100R005C00SPC800

OptiX OSN 8800/6800/3800 V100R005C00SPC900

OptiX OSN 8800/6800/3800 V100R006C00SPC100

 

3. Both the active and standby SCC boards are online. In addition, the active SCC board is in a

slot of the smaller-number while the standby SCC board is in the larger-number slot.

SCC

SCC

Figure 1 shows the slot layout of the OptiX OSN 3800 (DC powered).

 

Chassis

Chassis

Note: The board in the blue circle in the figure above indicates the SCC board in the

smaller-number slot, and that in the red circle indicates the SCC board in the larger-number slot.

 

Figure 2 shows the slot layout of the OptiX OSN 6800.

 

 

Subrack

Subrack

Figure 3 shows the slot layout of the OptiX OSN 8800 T32.

 

 

OSN 8800

OSN 8800

Figure 4 shows the slot layout of the OptiX OSN 8800 T64.

 

 

OSN 8800 T64

OSN 8800 T64

Symptom:

The fan rotation speed does not match the subrack temperature.

Identification method:

Both the active and standby SCC boards are online. In addition, the active SCC board

is in a slot of the smaller-number while the standby SCC board is in the larger-number slot.

 

[Root Cause]

For the OptiX OSN NG WDM of a version earlier than V100R006C01SPC200, subrack

temperature detection is implemented by the SCC board in the larger-number slot. It is

implemented by the SCC board in the smaller-number slot only when the SCC board in

the larger-number slot is asserted offline. The fan rotation speed control however, is

always implemented by the active SCC board based on its obtained subrack temperature.

When the active SCC board is the SCC board in the smaller-number slot, the fan rotation

speed does not match with the subrack temperature.

 

[Impact and Risk]

1. If the subrack temperature is low but the fan rotation speed is high, the life span of the

FAN board will be shortened.

2. If the subrack temperature is high but the fan rotation speed is low, the FAN board

will be burnt.

 

[Measures and Solutions]

Recovery measures:

Perform an active/standby SCC switchover so that the active SCC board is in the larger-number

slot specific for the SCC board.

Workarounds:

See “Recovery measures” as described previously.

Preventive measures:

Upgrade the NE version to V100R006C01SPC200 or a later mainstream version.

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