# How do I calculate the number of power modules required in a CE12800 switch

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You can use Hardware Configuration Tool to calculate the number of power modules required in a CE12800 switch. The calculator is also integrated in the UniSTAR system.

You can also use the following method to calculate the number of power modules required:

Minimum number of power modules required = Sum of maximum power consumption of all working modules in the switch/Maximum power of a single power module + 1

For example, a CE12808 switch uses 2700 W AC power modules and is configured with two CE-CMUAs, five CE-SFU08As, two CE-MPUAs, and two CE-L48XS-EC line cards. Based on the power consumption values of the cards provided in the "Card" section of the CloudEngine 12800 Series Switches Hardware Description and the power consumption of the chassis (including fans) and power modules, the sum of maximum power consumption of all modules can be obtained: 2519 W. Therefore, a minimum of one 2700 W power module is required.

To ensure power reliability of a CE12800 switch, it is recommended that you use the N+N backup mode with double power supply systems so that the failure of a single power supply system will not cause power failure or restart of the switch. In the preceding example, the 1+1 backup mode is recommended.

###### Other related questions:

Question about power distribution on S series switches
For a fixed switch:
One or two power modules can be installed on a fixed switch. If two power modules are installed, they work in 1+1 redundancy mode.
For a modular switch:
The number of power modules installed on a modular switch depends on the maximum power actually required by the switch. Ensure that the maximum output power of power modules is larger than the maximum power actually required by the system. For example, the maximum power required by the system is 4000 W. If two 2200 W power modules are installed in the chassis, they work in 2+0 mode. If three 2200 W power modules are installed, they work in 2+1 redundancy mode. If four 2200 W power modules are installed, they work in 2+2 redundancy mode.
To query the maximum power required by the system, see

Power Consumption Calc.

How do I calculate the number of power modules required on a CE switch
Description

How do I calculate the number of power modules required on a CE switch?

Solution

Calculate the total power consumption of all working modules on the switch and divide this value with the maximum power that a power module can provide. Add 1 to the integer part of the calculation result. The sum N is minimum number of power modules required for the switch. In real-world applications, more than N power modules are configured to implement power redundancy. The power modules can work in N+1 or N+N backup mode.

For example, a CE12808 chassis uses 2700 W AC power modules and is configured with two 48*10GE interface cards, five CE-SFU08A cards, and two MPUs.

With this configuration, the maximum power consumption of the chassis is 2455 W. 2455 W divided by 2700 W is smaller than 1, so the integer part is 0. That is, a minimum of one power module is required (0 + 1 = 1). Considering power redundancy, the number of power modules used on the chassis is:

In N+1 backup mode: N + 1 = 1 + 1 = 2

In N+N backup mode: N + N = 1 + 1 = 2

For details, visit http://support.huawei.com/onlinetoolsweb/network_configtool/index.jsp?lang=en&audience=enterprise

How do I calculate AP power
Assume the chip of the AP3010DN-AGN provides a transmit power of 50 mW, and the AP3010DN-AGN has two antennas, each of which can increase the transmit power by 2.5 times. The AP transmit power is 250 mW (50 x 2.5 x 2 = 250 mW), that is 24 dBm, which is calculated based on the formula: 10log (50 x 2.5 x 2) = 17 + 4 + 3 = 24 dBm.

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