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## combined power mode for 6500 switch

Hi every body

I hope everyone is having a great weekend.

The following discussion is based on cisco cat 6500 switches with two power supplies: p1 and p2.  . Both power supplies are running in combined mode .Each power supplies is rated with 500 watts max( I just picked 500 watts for simplicity)

#### Combined mode

In combined mode, each power supply provides approximately 83% of its  capacity to the chassis. This allows for greater utilization of the  power supplies and potentially increased PoE densities

1) Let say  our specific 6500 switch's configuration requires 1000 watts. We have two power supplies p1 and p2 ,each with rated power of 500 watts.  Both power supplies must operate in combined mode.  Will power supplies be able to meet the total load power requirement of  1000 watts?

Here is my understanding :

The maximum power delivered by each power supplies is 83 percent of its rated power, assuming power supplies are running in combined mode.

So Maximum power delivered by power supplies =  83% of p1+ 83% of p2

=  83% of 500 + 83% of 500

= 415 +415

=830 watts

Thus the required load of 1000 watts can not be met by our power supplies in combined mode.

====================================================================

2 )Suppose our switch's switch configuration needs 500 watts.  Again our power supplies each rated with 500 watts, are configured for combined mode.

How much power is being delivered by each power supply?  Is it 83 percent of the total load i.e 500 watts?

Thanks and have a great weekend.

Everyone's tags (6)
2 ACCEPTED SOLUTIONS

Accepted Solutions
Rising star

## Re: combined power mode for 6500 switch

hi,

#1 No. it wont provide all 1000 watts. it is always max. of 167% of total combined power (2 * 83% of the lower Wattage PS).

not meeting the full power requirement of the system, causes inline devices and line cards to be shut down by the power management software so the total consumption falls within operating power capabilities.

also, the order of the shut down process would be from the highest numbered port to the lowest numbered port, then from the bottom slot to the upper one.

#2 As with its name, it is combined and devided almost evenly between each power supply. ie: near 50% of the total system Watts requiremnt from each pwr supply AND up to 83% of each supply's capacity max.

you can view your system power usage and configuration by issuing the following command: show power

plz Rate if it helped.

Soroush

Hope it Helps!

Soroush.
Rising star

## combined power mode for 6500 switch

Hi Reza,

Combined: The total power available to the system is approximately 167 percent of the lower-wattage power supply. The system powers up as many modules as the combined capacity allows. If the higher-wattage power supply fails, the lower-wattage supply might also shut down due to overcurrent protection to prevent damage to the lower-wattage power supply.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/hardware/Chassis_Installation/Cat6500/0apwsply.html#wp1030039

Hope it Helps!

Soroush.
4 REPLIES 4
Rising star

## Re: combined power mode for 6500 switch

hi,

#1 No. it wont provide all 1000 watts. it is always max. of 167% of total combined power (2 * 83% of the lower Wattage PS).

not meeting the full power requirement of the system, causes inline devices and line cards to be shut down by the power management software so the total consumption falls within operating power capabilities.

also, the order of the shut down process would be from the highest numbered port to the lowest numbered port, then from the bottom slot to the upper one.

#2 As with its name, it is combined and devided almost evenly between each power supply. ie: near 50% of the total system Watts requiremnt from each pwr supply AND up to 83% of each supply's capacity max.

you can view your system power usage and configuration by issuing the following command: show power

plz Rate if it helped.

Soroush

Hope it Helps!

Soroush.
VIP Expert

## combined power mode for 6500 switch

Hi Sarah,

I don't think that the 83% is correct.  According to the 12.2(SX) config guide, it is the capacity of both PSUs.  There is no mention of a percentage. In your case it is the full 1000 Watts.

To disable redundancy, use the

combined

keyword. In a nonredundant configuration, the power available to the  system is the combined power capability of both power supplies. The  system powers up as many modules as the combined capacity allows.  However, if one power supply fails and there is not enough power for all  of the previously powered-up modules, the system powers down those  modules.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/pwr_envr.html#wp1020351

HTH

Rising star

## combined power mode for 6500 switch

Hi Reza,

Combined: The total power available to the system is approximately 167 percent of the lower-wattage power supply. The system powers up as many modules as the combined capacity allows. If the higher-wattage power supply fails, the lower-wattage supply might also shut down due to overcurrent protection to prevent damage to the lower-wattage power supply.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/hardware/Chassis_Installation/Cat6500/0apwsply.html#wp1030039

Hope it Helps!

Soroush.
Contributor

HI Reza