The Power over Ethernet allow to transport power and network by using signal Ethernet cable. However, the distance is limited to 100 meters. The remain voltage will drop down to less than 38 DC voltage after 100 meters. The standard PoE system requires 38 DC voltage . Adding the PoE extender to repeat the network signal and increase the voltage. One PoE extend provides 100 meters extra. 4 PoE extender daisy chain setup will provide 500 meters distance in total. Remain power is thing you need to concern after long distance transmit. The power will be converted to heat and loss on the cable. It is always need to make sure remain power is enough to supply the frontend IP cameras.