Power Over Ethernet Switches

[Desert_AIP]

Can someone please answer this question if they have experience with it? My whole network is gigabit and I am spec-ing out my POE network. Do I NEED gig there or I should be fine with 10/100 for the camera stuff. And I am talking 1MP+ cameras (Dahua mid range comes to mind)...how much is their traffic and how chatty does the network get if you have a couple (6-10) of these!

PoE cameras can't be gigabit because one of the pairs is used for power.
So they only connect at megabit speeds.
The advantage to using a gigabit switch is the network backbone is gigabit.
So if you have multiple megabit cameras on a gigabit switch talking to other gigabit devices, you should get max throughput.
Using a megabit switch will produce a bottle neck with multiple cameras.

This all depends on resolution of the cameras and whether or not you are recording.
Pushing streaming megapixel video to a NAS takes a lot of bandwidth.
I have a 1.3 MP camera that uses approximately 45MB of space per minute that is streaming to,a 6TB NAS.
Multiply that by more than a couple cameras and you may experience latencies.

 

[tmbrown97]

PoE cameras can't be gigabit because one of the pairs is used for power.
So they only connect at megabit speeds.

Not actually correct.  Gigabit POE exists and is perfectly standard.  Gigabit data and power can exist on the same pairs.  I use Cisco 3560X switches which are GigE/POE - and on my old Cisco VOIP network, my desk phones were gigabit POE powered with a 2-port gigabit switch internal so the attached PC's could be gigabit and still only use one wire for both.
 
It's cheaper to make 10/100 POE though, that's for sure - and if you think of it, there's absolutely no point in having a gigabit POE camera.  Any camera that's pushing more than 6mb of data is going to cause way too much network traffic in scale.  
 
Lets take one example - a 5MP network camera (2560 x 1920/more than double 1080p) running on high quality, MPEG4 at 30FPS would use approx 37.43Mbps... nowhere near the limits of 10/100.  On a more realistic scale, a 2MP camera in h.264 running full 30FPS uses under 10Mbps.  
 
That is why cameras aren't gigabit - there's zero point.  That said, and switch that's 10/100 POE with gigabit uplink should more than suffice.

 

[Del91574]

That is all true, however there are practicality issues with some cameras.
 
We've had some issues with Arecont and Mobotix cameras eating up bandwidth on a port (NIS complained) but the crossover point is they're essentially 2-4 cameras/port.

 

[pete_c]

Personally at home (on my little network) these days I am moving towards separating the IP POE cameras from the IP POE touchscreens both relating to physically separated switches and power supplies.  That is me though.    
 
Many many years ago in the days of "precious" bandwidth (enterprise LAN and WAN) and a push for many security IP cameras (early 2000's) I did suggest to create a separate bucket of money for the endeavor separating both local and WAN connected IP cameras from the rest of the network based on many "what if" scenarios and the amount of traffic generated by said cameras back then (all SD IP cameras).  I was just testing "stuff" and was replacing cameras due to their destruction occuring every week or so.  (with was a PITA).  Concurrently I was also working on changing / testing bandwidth requrements for high definition FID's moving from broadband stuff to strickly IP.  Again separating the networks physically locally.   I would probably suggest the same for enterprise campus environments today.   Many times folks superficially treat a network environment similiar to an electrical environment meaning that if the infrastructure is there (ie electrical outlets) they are free to utilize it for whatever they need it for; which really is very superficial "me first attitude"). (that is my opinion though).  In enterprise type endeavors it usually comes down to what department has the budgeting and largest "stick".  
 
I did also notice too that my newer HD cameras mfg suggest a 2 AMP power supply versus a 1 AMP power supply; this is kind of a large draw of power for a POE IP based camera. 

 

[Desert_AIP]

Work2Play, I stand corrected.
Are the gigabit cameras relatively new?

 

[tmbrown97]

I can't say I've seen gigabit cameras because, as I demonstrated above, there's no good point...  also I was mostly trying to point out that gigabit and POE are neither mutually exclusive - you can have both.