Just make sure that the switch has enough POE ports and a power budget sufficient to power all of the cameras. Many 8 port POE switches have 4 POE ports and 4 data-only ports. For instance, the 5 port switch dalepa recommended before knowing you had 5 cameras has 4 POE ports and one data port. Perfect for 4 cameras and the link back to the rest of your network but no good for you. You can get by with 5 cams by using a common 8 port POE switch that has 4 POE ports by adding a 48v POE injector after one of the data ports or powering one camera via 12v if it has a 12v dongle. We'll assume that your 5 cams run from POE (802.3af), not POE+ (802.3at), correct? Usually only big PTZs or cameras with heaters require POE+.