Campus Switching and Routing

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How many PoE devices can a switch support?

Hi experts,

 

I wonder how many PoE devices my switch can support. My switch is an Aruba 2930F (JL256A), which has a PoE power of 370 W PoE+ according to the datasheet. If my VoIP phones are 802.3af class 2, which requires a minimun of 7 W from a switch, does that mean that my switch can support 370/7=52.85 --> 52 phones?

 

Regards,

Julián

mkk
Contributor II

Re: How many PoE devices can a switch support?

Yes, 370watt is dedicated to poe power, so you have 7.7watt per interface on a 48port switch...

But be sure that you calculate by the maximum power needed by your voip phone, not the minimum ;)
mkk
Contributor II

Re: How many PoE devices can a switch support?

Yes, 370watt is dedicated to poe power, so you have 7.7watt per interface on a 48port switch...

But be sure that you calculate by the maximum power needed by your voip phone, not the minimum ;)
Aruba Employee

Re: How many PoE devices can a switch support?

Hello,

 

Aruba 2930F (JL256A) has 48 PoE+ Ports on the switch.  If the device is drawing up to 7 W then, this switch supports 48 devices since there are 48 PoE+ ports on the switch.  However, if the device draws more than 7 W then, the number supported PoE device would be lower.

 

Thank You,

Priyank Patel

Re: How many PoE devices can a switch support?

Hi guys,

 

Thanks for your interest. Sure, I didn't take into account the switch only has 48 PoE ports. I have a doubt, my phone datasheet says the following:

datasheet.JPG

But according to the ACMA certification guide:

acma_table.JPG

So, do I have to consider 2.3 or 7 W for PoE?

 

Regards,

Julián

Aruba Employee

Re: How many PoE devices can a switch support?

Greetings!

 

Even if you consider the worst case power draw of 7W, the 370W switch would still support the full 48 ports of PoE for the phones. 

 

That said, it's possible that the phone's manufacturer simply listed the wrong PoE class in their datasheet, and the power draw listed is the number you would use for planning purposes.



Matthew Fern | Technical Marketing Engineer, Wired Intelligent Edge
Aruba, a Hewlett Packard Enterprise Company
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