Can anyone explain the below image regarding power supply.

[Jobsp]

When I was checking the meraki poe switch (model - MS225-48FP) this shows there.  What is the meaning of each consumption, budgeted and their corresponding values?

[cmr]

Consumption is how much power is currently being used by PoE devices on that switch

Budgeted is how much all of the connected PoE devices have said they might need.  i.e. a wireless AP might ask for 30W, but actually be only using 12W when you checked.

[Jobsp]

What is the meaning of budgeted 1008 W/740 W. Here what does it mean by the values?Total power of the switch is 740w then what is 1008 w?

[cmr]

Switch PoE total power is 740W

Budgeted PoE power for all connected devices is 1008W

The budget can way exceed the total as devices hardly ever use what they budget.

[cmr]

If you go to the ports view and enable the PoE column, you can see how each device requests (and therefore the switch budgets) more empower than it generally uses:

 

 

[Jobsp]

Can u pls explain Is the poe device asking for 30 w or 10.2 w from the switch?

[ww]

At the moment 10.2.

But the could use up to 30, for example at the booting proces of the device

[cmr · Accepted solution]

The PoE devices is telling the switch that it might need as much as 30W (the budget), but at the time of looking they are only actually using 10.2W and 5.3W in my case.  Therefore the switch would have a PoE budget of 60W and consumption of 15.5W.

[GreenMan]

 Only just found this thread, when looking for something else.    Bear in mind with this, the screenshot here is taken from an MS switch, where overbudgeting is supported.   This is NOT the case for Catalyst-based switches (e.g. C9300) monitored / managed in the Dashboard.   These are strict about budgeting for the PoE class which the powered device is claiming.   If the device class says 30W, the switch reserves 30W, even if it is only initially consuming 10W.    Once the available budget (the 740W in this instance) is "consumed" by the budget, new PoE devices will not power up, even if actual consumption is below that available.   This ensures that you do not find a circumstance where already powered devices want to draw more later, but suddently find they can't.   Take particular care if you are looking at replacing older MS switches with new Catalyst-based switches.

[cmr]

Wow that's a backwards step!  I'm sure older Catalyst switches (2960s etc.) didn't do this, or perhaps the devices at the time didn't consume enough power for us to be ever hit by this.

@GreenMan do you know if this is planned to be fixed, or is it thought to be better as customers need to buy bigger power supplies than they'll ever likely need?

[GreenMan]

To my knowledge this is how Catalyst has always worked - it is how it's designed, so there's no plan to change it, that I'm aware of.   As devices (particularly APs) have started to consume more, this may indeed be why you've not come across it before.    I can't comment to the (slightly cynical..?) thought you've had as to the 'why' (I'm not in product development) - though I can see why it would have occurred to you 😁.

My guess would be that it is a more 'safety first' approach;  if you power a device up, but maybe have it stop working properly at some ill-defined point in the future, when it needs to draw more, that could have serious ramifications.   It could well be better to power it up knowing you can always provide what it's told you it might require?   And for the admin to know right from the outset that they need to PoE budget more accurately?   I can see it's an eyebrow-raiser though, so my apologies for that - it is why I mentioned it here though...