Hello, 
  
Hell of a first post incoming. 
  
I have total 7 PoE cameras installed in a manufacturing facility.  
Since i had no experience, i did the best i could while designing the system. 
I have one camera per PoE switch -> data switch -> PC/Server (Scheme added)  
I got the system up and working only this way when there were no cameras connected to "Data switch" hence the reason calling it data. 
So i have an issue where 4 of the cameras are unstable (right side data switch( cabling marked with "?")) Long loading times, connection drops, latency etc. 
No cable (Cat5e) should be longer than 100m/330ft.  
Power is supplied from single wall socket to whole system.  
Switches are 40W maximum output supporting IEEE802.3at, af.  10/100Mbps (up to 150meters) 
Most powerful/biggest camera max 20W usage. 
Usually when one camera drops connection, all 4 go down from that side. 5 seconds to couple of minutes. Usually couple of seconds. 
If it was power requirement, all 7 cameras would drop, same with bandwith limit i guess. 
The connection drops usually occur when i try to access camera via ip or simply trying to PTZ. 
  
I've been thinking about: 
New/secondary cable from data to data swith as it's been patched couple of times. (Rats bigger than cats, video on request) 
An PCI-e networking card specifically for cameras? 
UPS 
Gigabit data switch 
Eliminating link between two data switches and bringing two cables to server from each data switch. 
  
Any suggestions, troubleshooting/testing ideas welcome. 
  
Best Regards, 
H. 
  
PS! There is a router between pc and data switch. Also i have few empty leads for future cameras. 
  
Edit// 2 of the cameras on connection drop side are 1080p (one PTZ) and 2 704x576px (both PTZ)