PoE for beginner

[Sparxxx]

Hi there

I would need your help regarding PoE switches.
The idea is that I need to buy two new gigabit switches (5-8 ports):
1x PoE switch in the Office room
1x PoE switch in living room
They will be connected through in-wall Ethernet plug.

Questions:
1 of the switches will have to be connected to power, right? The other one will just get the power over the PoE port.
Does the in-wall Ethernet plug send the power for PoE?

What switches do you recommend? I don't need anything fancy, just gigabit PoE and stable. They should support multicast though.

Thanks!

 

[thiggins]

You can't power one PoE switch from another. PoE ports are power sources only.

 

[Sparxxx]

Ok, this is new to me.
So no switch can be powered by another switch over PoE?.
I saw some from Ubiquiti that have PoE in/out, PoE passthrough etc.

 

[thiggins]

Ok, this is new to me.
So no switch can be powered by another switch over PoE?.
I saw some from Ubiquiti that have PoE in/out, PoE passthrough etc.

I was wrong. There are switches that can be PoE powered (https://mikrotik.com/product/RB260GS), but are not themselves PoE switches.

If a PoE switch were powered from PoE, it could only source at most as much power as it obtained from the single PoE port powering it. Probably not very useful.

 

[Sparxxx]

Yes, makes sense but in my case I only need 2 switches. 1 that can power the other one . Any recommendations?.

 

[umarmung]

There are PoE passthrough switches or routers (since most routers have a switch chip too). I have no specific recommendations since its not a configuration I have used.

However, these are devices I have seen:

Netgear GS105PE
D-Link DGS-1100-05PD
Intellinet 561082
Mikrotik RB260GSP
Mikrotik hEX PoE (router)

Just decide whether you want managed or unmanaged, know your PoE device budget requirements, look carefully through their PoE budget power and their own requirement and check the reviews for any serious issues. Prefer anything that takes in PoE+ (802.3at) and outputs PoE (802.3af), because physics , i.e. the switch itself will need to be powered so need capability of maximum input budget for maximum output budget.

Note the Mikrotiks are for SOHO, not consumer devices, and are generally anything but easy to configure. They will likely also use non-standard PoE, i.e. not 802.3af/at, but Passive PoE.

 

[CaptainSTX]

Hi there

I would need your help regarding PoE switches.
The idea is that I need to buy two new gigabit switches (5-8 ports):
1x PoE switch in the Office room
1x PoE switch in living room
They will be connected through in-wall Ethernet plug.

Questions:
1 of the switches will have to be connected to power, right? The other one will just get the power over the PoE port.
Does the in-wall Ethernet plug send the power for PoE?

What switches do you recommend? I don't need anything fancy, just gigabit PoE and stable. They should support multicast though.

Thanks!

Take a look at what TexasPOE offers on their site or their store on Amazon. You might find it simplier and less expensive to use a power injector. I think I paid less than US$10.00 for a set of injectors which I use to power my switch and it maintains the gigabit connection between my router and the switch. When you are looking for injectors lots of Fast Ethernet rated injectors available cheap but you need to pay attention and look a little harder for gigabit equipment.

You will also need to do a voltage loss calculation as the voltage loss on long runs makes POE not possible. Again on the above mentioned site they have a nice calculator.

 

[Despacitomiko]

Here is a 8 port gigabit poe+ switch: https://www.fs.com/products/35290.html It’s a managed switch with 2 SFP ports. A video is included in the product page to help connect the switch.

 

[Sparxxx]

Thanks, I'll have a look.

 

[System Error Message]

@thiggins there are switches that can both power themselves and provide POE out, mikrotik has a few but calls them routers instead. For instance i believe the RB3011 has both POE in and POE out but only on 1 port.

My advice for any POE newb is 1) check your protocols, 2) never get an unmanaged POE switch, always get a managed one that lets you monitor and set POE, 3) use the best cable you get, make sure the cable is fully copper core (not copper clad) and has the largest conductor diameter (expressed as AWG, the smaller the AWG to bigger but for the conductor). Also make sure to minimise cable length and always use the best PSUs and ensure that the voltage that can be provided is high to account for voltage drop. Stick to active POE as it allows for negotiation unlike with passive POE and always make sure your POE out capability is far more than your device needs as there will be significant losses.

I hope i've covered the basics, dont forget the fire extinguisher as if you bought a crappy switch like dlink, you may want to beat it .

 

[umarmung]

Here is a 8 port gigabit poe+ switch: https://www.fs.com/products/35290.html It’s a managed switch with 2 SFP ports. A video is included in the product page to help connect the switch.

That FS managed PoE switch, while magnificent , does not appear to be PoE passthrough.